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Page No 1.12:

Question 1:

How many milligrams make on kilogram?

Answer:

Ten lakh or one million (10,00,000) milligrams make one kilogram.

Page No 1.12:

Question 2:

A box of medicine tablets contains 2,00,000 tablets each weighing 20 mg. What is the total weight of all the tablets in the box in grams? In kilograms?

Answer:

∵ Each tablet weighs = 20 mg

∴ The weight of 2,00,000 tablets = 2,00,000 × 20 = 40,00,000 mg
​ ∴ The total weight of all the tablets in the box = 40,00,000 mg
 
We know 1 g = 1,000 mg
∴ Weight of the box having all tablets = 40,00,000 ÷ 1,000 = 4,000 g

And, as 1 kg = 1,000 g
∴ Weight of the box having all tablets = 4,000 ÷ 1,000 = 4 kg

Page No 1.12:

Question 3:

Population of Sundar nagar was 2,35,471 in the year 1991. In the year 2001 it was found to have increased by 72,958. What was the population of the city n 2001?

Answer:

The population of Sundar Nagar in 2001 = Sum of the population of city in 1991 + Increase in population over the given time period
∵ The population of Sundar Nagar in 1991 = 2,35,471
∵ Increase in population over the given time period = 72,958
∴ 
The population of Sundar Nagar in 2001 = 2,35,471 + 72,958 = 3,08,429

Page No 1.12:

Question 4:

A book exhibition was held for four days in a school. The number of tickets sold at the counter on the first, second, third and final days wre respectively 1094, 1812, 2050 and 2751. Find the total number of tickets sold on all the four days.

Answer:

Total number of tickets sold on all four days is the sum of the tickets sold on the first, second, third and final days.
∴ Total number of tickets sold on all four days = 1,094 + 1,812 + 2,050 + 2,751 = 7,707

Page No 1.12:

Question 5:

The town newspaper is published everyday. One copy has 12 pages. Everyday 11,980 copies are printed. How many pages are in all printed everyday? Every months?

Answer:

∵ Number of pages in 1 copy of newspaper = 12

∴ Number of pages in 11,980 copies of newspaper = 11,980 × 12 = 1,43,760

 Thus, 1,43,760 pages are printed every day.

Now, number of pages printed every day = 1,43,760
∴ Number of pages printed in a month = 1,43,760 × 30 = 43,12,800

Thus, 43,12,800 pages are printed in a month.

Page No 1.12:

Question 6:

A machine, on an average, manufactures 2825 screws a day.  How many screws did it produce in the month of January 2006?

Answer:

∵ Number of screws produced by a machine in a day = 2,825
∴ Number of screws produced by the same machine in the month of January 2006 = 2,825 × 31 = 87,575
    Thus, machine produced 87,575 screws in the month of January 2006.

Page No 1.12:

Question 7:

A famous cricket player has so far scored 6978 runs in test matches. He wishes to complete 10,000 runs. How many more runs does he need?

Answer:

Runs scored by cricket player in test matches = 6,978

∴ Remaining runs required to complete 10,000 runs = 10,000 − 6,978 = 3,022
 
Thus, the player needs to score 3,022 more runs to complete 10,000 runs.

Page No 1.12:

Question 8:

Ravish has Rs 78,592 with him. He placed an order for purchasing 39 radio sets at Rs 1234 each. How much money will remain with him after the purchase?

Answer:

Ravish's initial money = ₹78,592
He purchased 39 radio sets at ₹1,234 each.
∴ Money spent by him on purchasing 39 radio sets = ₹1,234 × 39 = ₹48,126

∴ Remaining money with Ravish after the purchase = Initial money − Money spent on purchasing 39 radio sets = ₹78,592 − ₹48,126 = ₹30,466

Thus, ₹30,466 is left with him after the purchase.
 

Page No 1.12:

Question 9:

In an election, the successful candidate registered 5,77,570 votes and his nearest rival secured 3,48,685 votes. By what margin did the successful candidate win the election?

Answer:

Margin of victory in the election for the successful candidate = Number of votes registered by the winner − Number of votes secured by nearest rival candidate
 Votes registered by the winner = 5,77,570
 Votes secured by the rival = 3,48,685
 Margin of victory for the successful candidate = 5,77,570 − 3,48,685 = 2,28,885

Page No 1.12:

Question 10:

To stitch a shirt 2 m 15 cm cloth is needed. Out of 40 m cloth, how many shirts can be stiched and how much cloth will ramain?

Answer:

∵ Total length of available cloth = 40 m = 4,000 cm (1 m = 100 cm)

∵ Length of cloth required to stitch a shirt = 215 cm =  200 + 15 = 215 cm 
∴ The number of shirts that can be stitched from the 40-metre cloth = 4,000/215 = 18.60
As the number of shirts has to be a whole number, we consider the whole part only. That is, 18 such shirts can be stitched.

∴ Cloth required for stitching 18 shirts = 215 × 18 = 3870 cm
∴ Remaining cloth = 4,000 − 3870 = 130 cm = 1.3 m

Page No 1.12:

Question 11:

A vessel has 4 litre and 650 ml of curd. In how many glasses, each of 25 ml capacity, can it be distributed?

Answer:

Number of glasses in which curd can be distributed = Total amount of curd/Capacity of each glass.

Total amount of curd in the vessel =  4,650 mL =  4,000 + 650 = 4,650 mL (1 L = 1,000 mL)
Capacity of each glass = 25 mL
∴ Number of glasses in which curd can be distributed = 4,650/25 = 186

Page No 1.12:

Question 12:

Medicine is packed in boxes, each such box weighing 4 kg 500 g. How many such boxes can be loaded in a van which cannot carry beyond 800 kg.

Answer:

∵ Total capacity of a van carrying boxes of medicines = 800 kg = 8,00,000 g (1 kg = 1,000 g)

∵ Weight of each packed box  = 4,500 g  = 4,000 + 500 = 4,500 g
∴ Total number of boxes that can be loaded in the van = 8,00,000/4,500 = 177.77

The obtained number of boxes is not a whole number.
∴ Weight of 177 boxes = 177 ´ 4,500 = 7,96,500 g (under permissible limit)
∴ Weight of 178 boxes = 178 ´ 4,500 = 8,01,000 g (beyond permissible limit)
Therefore, we can't load 178 boxes; hence, we can say that 177 boxes can be loaded in the van.

Page No 1.12:

Question 13:

The distance between the school and the house of a student is 1 km 875 m. Everyday she walks both ways between her school and home. Find the total distance covered by her in a week.

Answer:

∵ Distance between the school and the house of a student = 1,875 m = 1,000 + 875 = 1,875 m (1 km = 1,000 m)
∵ Distance covered by a student in a day = 2 × 1,875 = 3,750 m
 ∴ Total distance covered by her in a week = 7 × 3,750 = 26,250 m = 26.25 km



Page No 1.17:

Question 1:

Round off each of the following numbers to nearest tens:

(i) 84
(ii) 98
(iii) 984
(iv) 808
(v) 998
(vi) 12,096
(vii) 10,908
(viii) 28,925

Answer:

(i) 80
(ii) 100
(iii) 980
(iv) 810
(v) 1,000
(vi) 12,100
(vii) 10,910
(viii) 28,930

Page No 1.17:

Question 2:

Round off each of the following numbers to nearest hundreds:

(i) 3,985
(ii) 7,289
(iii) 8,074
(iv) 14,627
(v) 28,826
(vi) 4,20,387
(vii) 43,68,973
(viii) 7,42,898

Answer:

(i) 4,000
(ii) 7,300
(iii) 8,100
(iv) 14,600
(v)​ 28,800
(vi) 4,20,400
(vii) 43,69,000

(viii) 7,42,900

Page No 1.17:

Question 3:

Round off each of the following numbers of the nearest thousands:

(i) 2,401
(ii) 9,600
(iii) 4,278
(iv) 7,832
(v) 9,567
(vi) 26,019
(vii) 20,963
(viii) 4,36,952

Answer:

(i) 2,000
(ii) 10,000
(iii) 4,000
(iv) 8,000
(v) 10,000
(vi) 26,000
(vii) 21,000
(viii) 4,37,000

Page No 1.17:

Question 4:

Round off each of the following to the nearest tens, hundreds and thousands:

(i) 964
(ii) 1,049
(iii) 45,634
(iv) 79,085

Answer:

     Tens               Hundreds                  Thousands 
(i) 970                    1,000                     1,000
(ii)1,050                 1,000                     1,000
(iii) 45,630              45,600                   46,000
(iv) 79,090              79,100                   79,000

Page No 1.17:

Question 5:

Round off the following measures to the nearest hundreds:

(i) Rs 666
(ii) Rs 850
(iii) Rs 3,428
(iv) Rs 9,080
(v) 1,265 km
(vi) 417 m
(vii) 550 cm
(viii) 2,486 m
(ix) 360 gm
(x) 940 kg
(xi) 273 l
(xii) 820 mg

Answer:

(i) ₹700
(ii) ₹900
(iii) ₹3,400
(iv) ₹9,100
(v) 1,300 km
(vi) 400 m
(vii) 600 cm
(viii) 2,500 m
(ix) 400 gm
(x) 900 kg
(xi) 300 L
(xii) 800 mg

Page No 1.17:

Question 6:

List all numbers which are rounded off to nearest ten as 370.

Answer:

365, 366, 367, 368, 369, 370, 371, 372, 373, 374

Page No 1.17:

Question 7:

Find the smallest and greatest numbers which are rounded off to the nearest hundreds as 900.

Answer:

Smallest number = 850
Greatest number = 949

Page No 1.17:

Question 8:

Find the smallest and greatest numbers which are rounded off to the nearest thousands as 9000.

Answer:

Smallest number = 8,500

Greatest number = 9,499



Page No 1.20:

Question 1:

Estimate the following by rounding off each factor to nearest hundreds:

(i) 730 + 998
(ii) 796 − 314
(iii) 875 − 384

Answer:

(i) 700 + 1,000 = 1,700
(ii) 800 − 300 = 500
(iii) 900 − 400 = 500

Page No 1.20:

Question 2:

Estimate the following by rounding off each factor to nearest thousands:

(i) 12,904 + 2,888
(ii) 28,292 − 21,496

Answer:

(i) 13,000 + 3,000 = 16,000
(ii) 28,000 − 21,000 = 7,000

Page No 1.20:

Question 3:

Estimate the following by rounding off each number to its greatest place:

(i) 439 + 334 + 4,317
(ii) 8,325 − 491
(iii) 1,08,734 − 47,599
(iv) 898 × 785
(v) 9 × 795
(vi) 87 × 317

Answer:

(i) 400 + 300 + 4,000 = 4,700
(ii) 8,000 − 500 = 7,500
(iii) 1,00,000 − 50,000 = 50,000
(iv) 900 ×
800​ = 7,20,000
(v) 10 × 800​ = 8,000
(vi) 90 × 300​ = 27,000​

Page No 1.20:

Question 4:

Find the estimated quotient for each of the following by rounding off each number of its greatest place:

(i) 878÷28
(ii) 745÷24
(iii) 4489÷394

Answer:

(i) 900 ÷ 30 = 30
(ii) 700 ÷ 20 = 35
(iii) 4,000 ÷ 400 = 10



Page No 1.25:

Question 1:

Write the roman-numerals for each of the following:

(i) 33
(ii) 48
(iii) 76
(iv) 95

Answer:

(i) XXXIII
(ii) XLVIII
(iii) LXXVI
(iv) XCV

Page No 1.25:

Question 2:

Write the following in Roman numerals:

(i) 154
(ii) 173
(iii) 248
(iv) 319

Answer:

(i) CLIV
(ii) CLXXIII
(iii) CCXLVIII
(iv) CCCXIX

Page No 1.25:

Question 3:

Write the following in Roman numerals:

(i) 1008
(ii) 2718
(iii) 3906
(iv) 3794

Answer:

(i) MVIII
(ii) MMDCCXVIII
(iii) MMMCMVI
(iv) MMMDCCXCIV

Page No 1.25:

Question 4:

Write the following in Roman numerals:

(i) 4201
(ii) 10009
(iii) 44000
(iv) 25819

Answer:

(i) IVCCI
(ii) XIX
(iii) XLIV
(iv) XXVDCCCXIX

Page No 1.25:

Question 5:

Write the following in Hindu-Arabic numerals:

(i) XXVI
(ii) XXIX
(iii) LXXII
(iv) XCI
(v) LXXXV
(vi) XCIX
(vii) LXXXIX
(viii) XCVII

Answer:

(i) 10 + 10 + 6 = 26
(ii) 10 + 10 + 9 = 29
(iii) 50 + 10 + 10 + 2 = 72
(iv) (100 − 10) + 1 = 91
(v) 50 + 10 + 10 + 10 + 5 = 85
(vi) (100 − 10) + 9 = 99
(vii) 50 + 10 + 10 + 10 + 9 = 89
(viii) (100 − 10) + 7 = 97

 

Page No 1.25:

Question 6:

Write the corresponding Hindu-Arabic numerals for each of the following:

(i) CIX
(ii) CLXXII
(iii) CCLIV
(iv) CCCXXIX
(v) CDXLIX
(vi) DLXIX
(vii) DCCCLXI
(viii) CMXLIV

Answer:

(i) 100 + 9 = 109
(ii) 100 + 50 + 10 + 10 + 2 = 172
(iii) 100 + 100 + 50 + 4 = 254
(iv) 100 +100 +100 + 10 +10 + 9 = 329
(v) (500 − 100) + (50 − 10) + 9 = 449
(vi) 500 + 50 + 10 + 9 = 569
(vii) 500 + 100 + 100 +100 + 50 + 10 + 1 = 861

(viii) (1000 − 100) + (50 − 10) + 4 = 944

Page No 1.25:

Question 7:

Write the corresponding Hindu-Arabic numerals for each of the following:

(i) KXIX
(ii) KDLXV
(iii) KKCXXIII
(iv) KKKDCXL

Answer:

(i) 1,000 +10 + 9 = 1,019
(ii) 1,000 + 500 + 50 +10 + 5 = 1,565

(iii) 1,000 + 1,000 + 100 + 10 + 10 + 3 = 2,123
(iv) 1,000 + 1,000 + 1,000 + 500 + 100 + (50 − 10) = 3,640

Page No 1.25:

Question 8:

Write the following in Hindu-Arabic numerals:

(i) IVCDXLIC
(ii)VICKXLIX
(iii) IXCCCXCI
(iv) LXXIX

Answer:

(i) 4,000 + (500 − 100) + (50 − 10) + 4 = 4,444
(ii) 6,000 + (1,000 − 100)  + (50 − 10) + 9 = 6,949
(iii) 9,000 + 100 + 100 + 100 + (100 − 10) + 1 = 9,391
(iv) 70,000 + 9 = 70,009

Page No 1.25:

Question 9:

Which of the following are meaningless?

(i) XXXX
(ii) XLVI
(iii) VD
(iv) LXXXIX
(v) III¯CC
(vi) KKKCCXI
(vii) XD
(viii) VC
(ix) IC
(x) IL
(xi) XK
(xii) LVV

Answer:

The following numbers are meaningless:
(i) Since a symbol can't be repeated more than 3 times
(iii) Since V is never written to the left of a symbol of greater value
(v) Since bar is not placed above any symbol
(vii) Since X can't be subtracted from D
(viii) Since V is never written to the left of a symbol of greater value

(ix) Since I can be subtracted from V and X only
(x) Since I can be subtracted from V and X only
(xii) Since V can't be repeated

Page No 1.25:

Question 1:

The difference between the place value and face value of 8 in 658742 is
(a) 0
(b) 42
(c) 735
(d) 693

Answer:

The options given are incorrect.
The place value of 8 in 6,58,742 = 8 thousands = 8,000
The face value of 8 = 8
∴ Difference = 8,000 − 8 = 7,992



Page No 1.26:

Question 2:

The difference between the place values of 6 and 3 in 256839 is
(a) 3
(b) 9
(c) 6800
(d) 5930

Answer:

The options given are incorrect.
The place value of 6 in 2,56,839 = 6 thousands = 6,000
The place value of 3 in 2,56,839 = 3 tens = 30
 Difference = 6,000 − 30 = 5,970

Page No 1.26:

Question 3:

The difference of the smallest three digit number and the largest two digit number is
(a) 100
(b) 1
(c) 10
(d) 99

Answer:

(b) 1.

The smallest three-digit number is 100 and the largest two-digit number is 99.
∴ Difference = 100 − 99 = 1

Page No 1.26:

Question 4:

The largest three digit number formed by the digits 8, 5, 9 is
(a) 859
(b) 985
(c) 958
(d) 589

Answer:

(b) 985
The largest number is formed by writing the digits in descending order.

Page No 1.26:

Question 5:

The smallest three digit number having three distinct digits is
(a) 123
(b) 101
(c) 102
(d) 201

Answer:

(c) 102

The three distinct smallest digits are 0, 1 and 2. To form a smallest number using these digits, we need to arrange them in ascending order, but by this we get 012, which results in a two-digit number. So, the smallest three-digit number having distinct digits is 102.

Page No 1.26:

Question 6:

The largest three digit number having distinct digits is
(a) 987
(b) 789
(c) 999
(d) 900

Answer:

(a) 987

The largest three distinct digits are 9, 8 and 7. So, the largest number using these digits can be obtained by arranging the digits in descending order.

Page No 1.26:

Question 7:

The difference between the largest three digit number and the largest three digit number with distinct digits is
(a) 10
(b) 0
(c) 12
(d) 13

Answer:

(c) 12
The largest three-digit number = 999

The largest three-digit number with distinct digits = 987
∴ Difference = 999 − 987 = 12

Page No 1.26:

Question 8:

The product of the place values of two three in 53432 is
(a) 9000
(b) 90000
(c) 10000
(d) 99000

Answer:

(b) 90,000
The 3 in the second place from right is at tens place.
Therefore, the place value of 3 at tens place = 30.
The 3 in the fourth place from right is at thousands place.
Therefore, the place value of 3 at thousands place  = 3,000.
The product of the place values of two 3's = 3,000 × 30 = 90,000.

Page No 1.26:

Question 9:

The smallest counting number is
(a) 0
(b) 1
(c) 10
(d) None of these

Answer:

(b) 1

 The smallest digit is 0, but the smallest counting number is 1.

Page No 1.26:

Question 10:

The total number of 4 digit numbers is
(a) 8999
(b) 9000
(c) 8000
(d) 9999

Answer:

(b) 9,000

The smallest four-digit number is 1,000 and the largest four-digit number is 9,999.
∴ Total number of four-digit numbers = (9,999 − 1,000 ) + 1 = 9,000

Page No 1.26:

Question 11:

The number of 3 digit numbers formed by using 3, 5, 9 taking each digit exactly once, is
(a) 3
(b) 4
(c) 5
(d) 6

Answer:

(d) 6

The numbers are 359, 395, 539, 593, 935, 953.

Page No 1.26:

Question 12:

Total number of numbers which when rounded off to nearest ten give us 200 is
(a) 9
(b) 10
(c) 8
(d) 7

Answer:

(b) 10
The numbers that when rounded off to nearest tens give us 200 are 195, 196, 197, 198, 199, 200, 201, 202, 203, 204.

Page No 1.26:

Question 13:

The smallest number which when rounded off the nearest hundred as 600, is
(a) 550
(b) 595
(c) 604
(d) 599

Answer:

(a) 550
All numbers from 550 to 649 are rounded off to the nearest hundred as 600. Therefore, the smallest number is 550.

Page No 1.26:

Question 14:

The greatest number which when rounded off to the nearest thousand as 7000, is
(a) 6500
(b) 6549
(c) 7499
(d) 6499

Answer:

(c) 7,499

All numbers from 6,500 to 7,499 are rounded off to the nearest thousand as 7,000. Therefore, the greatest number is 7,499.

Page No 1.26:

Question 15:

The difference between the greatest and smallest numbers which when rounded off a number to the nearest tens as 540, is
(a) 10
(b) 9
(c) 8
(d) 10

Answer:

(b) 9
544 is the greatest number that when rounded off to the nearest tens will become 540.
535 is the least number that when rounded off to the nearest tens will become 540.
∴ Difference: 544 − 535 = 9

Page No 1.26:

Question 16:

The difference between the greatest and smallest numbers which when rounded off a number to the nearest hundred as 6700, is
(a) 100
(b) 99
(c) 98
(d) 101

Answer:

(b) 99
6,749 is the greatest number that when rounded off to the nearest hundred will become 6,700.
6,650 is the least number that when rounded off to the nearest hundred will become 6,700.
∴ Difference = 6,749 − 6,650 = 99

Page No 1.26:

Question 17:

The difference between the greatest and the smallest numbers which when rounded off to the nearest thousand as 9000, is
(a) 1000
(b) 990
(c) 999
(d) 900

Answer:

(c) 999
9,499 is the greatest number that when rounded off to the nearest thousand will become 9,000.
8,500 is the smallest number that when rounded off to the nearest thousand will become 9,000.
∴ Difference = 9,499 − 8,500 = 999

Page No 1.26:

Question 18:

Which of the following numbers is equal to 1 billion?
(a) 10 lakh
(b) 1 crore
(c) 100 lakh
(d) 100 crore

Answer:

(d) 100 crore

Page No 1.26:

Question 19:

In the international place vlaue system, we write one million for
(a) 1 lakh
(b) 10 lakh
(c) 100 lakh
(d) 1 crore

Answer:

(b) 10 lakh



Page No 1.6:

Question 1:

Insert commas in the correct positions and write the following numbers in words in the Indian system and the international system of numeration:

(i) 10000007
(ii) 1234567
(iii) 1010560
(iv) 1112323

Answer:

(i) 10000007

Indian system: 1,00,00,007, i.e., one crore and seven
International system: 10,000,007, i.e., ten million and seven


(ii) 1234567

Indian system: 12,34,567, i.e., twelve lakh, thirty-four thousand, five hundred and sixty-seven
International system: 1,234,567, i.e., one million, two hundred thirty-four thousand, five hundred and sixty-seven


(iii) 1010560

Indian system: 10,10,560, i.e., ten lakh, ten thousand, five hundred and sixty
International system: 1,010,560, i.e., one million, ten thousand, five hundred and sixty

(iv) 1112323

Indian system: 11,12,323, i.e., eleven lakh, twelve thousand, three hundred and twenty-three
International system: 1,112,323, i.e., one million, one hundred twelve thousand, three hundred and twenty-three

Page No 1.6:

Question 2:

Write each of the following expanded notation:

(i) 3057
(ii) 235060
(iii) 12345
(iv) 10205

Answer:

(i) 3000 + 50 + 7

(ii) 200000 + 30000 + 5000 + 60


(iii) 10000 + 2000 + 300 + 40 + 5

(iv) 10000 + 200 + 5

Page No 1.6:

Question 3:

Write each of the following in numeral form:

(i) Seventy thousand fifty three.
(ii) Six lakh two thousand nine.
(iii) Thrity lakh eleven thousand one.

Answer:

(i) 70,053
(ii) 6,02,009
(iii) 30,11,001

Page No 1.6:

Question 4:

 Write the number names of each of the following:

(i) 69,007
(ii) 8,08,090
(iii) 47,28,003
(iv) 5,03,04,012

Answer:

(i) Sixty-nine thousand and seven
(ii) Eight lakh, eight thousand and ninety
(iii) Forty-seven lakh, twenty-eight thousand and three
(iv) Five crore, three lakh, four thousand and twelve

Page No 1.6:

Question 5:

Write each of the following in numeral form:

(i) Eight million seven hundred eight thousand four.
(ii) Six hundred seven million twelve thousand eighty four.
(iii) Four billion twenty five million forty five thousand.

Answer:

(i) 8,708,004
(ii) 607,012,084
(iii) 4,025,045,000

Page No 1.6:

Question 6:

Write the number names of each of the following in international system of numeration:

(i) 435,002
(ii) 1,047,509
(iii) 59,064,523
(iv) 25,201,905

Answer:

(i) Four hundred thirty-five thousand and two
(ii) One million, forty-seven thousand, five hundred and nine
(iii) Fifty-nine million, sixty-four thousand, five hundred and twenty-three

(iv) Twenty-five million, two hundred one thousand, nine hundred and five

Page No 1.6:

Question 7:

Write 10075302 in words and rearrange the digits to get the smallest and the largest numbers.

Answer:

1,00,75,302 → One crore seventy-five thousand three hundred and two
Smallest number: 1,00,02,357 (write the digits in ascending order in such a way that total number of digits remain same)
Largest number: 7,53,21,000 (write the digits in descending order in such a way that total number of digits remain same)

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Question 8:

A certain nine digit number has only ones in ones period, only twos in the thousands period and only threes in millions period. Write this number in words in the Indian system.

Answer:

The number is 333, 222,111.
In Indian system, the number is written as 33,32,22,111 ⇒ Thirty-three crore thirty-two lakh twenty-two thousand one hundred and eleven.

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Question 9:

Find the place value of the digit 4 in each of the following:

(i) 74983160
(ii) 8745836

Answer:

(i)  4 ten lakhs (40,00,000)

(ii) 4 ten thousands (40,000)

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Question 10:

Determine the product of the place values of two fives in 450758.

Answer:

The number is 4,50,758.
The place values of 5 are 5 tens and 5 ten thousands.

The product of the place values of both fives = 5 tens × 5 ten thousands =  50 × 50,000 = 25,00,000.

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Question 11:

Determine the difference of the place values of two 7's in 257839705.

Answer:

The number = 25,78,39,705
The place value of first 7 (from right) = 25,78,39,705 ⇒ 7 hundreds = 700
The place value of the other 7 (from right) = 25,78,39,705 ⇒ 7 ten lakhs = 70,00,000
∴ Difference = 70,00,000 − 700 = 69,99,300

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Question 12:

Determine the difference between the place value and the face value of 5 in 78654321.

Answer:

The number = 7,86,54,321
The place value of 5 = 5 ten thousands = 50,000
The face value of 5 = 5

∴ Difference = 50,000 − 5 = 49,995

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Question 13:

Which digits have the same face value and place value in 92078634?

Answer:

The place value of a digit depends on the place where it occurs, while the face value is the value of the digit itself.
In a number, the digit that have same face value and place value are the ones digit and all the zeroes of the number.

Therefore, in 9,20,78,634,  4 (the ones digit) and 0 (the lakhs digit) have the same face value and place value.

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Question 14:

How many thousands make a million?

Answer:

1,000 thousands make a million.

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Question 15:

How many millions make a billion?

Answer:

1,000 millions make a billion.

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Question 16:

How many billion's make a trillion?

Answer:

1,000 billions make a trillion.

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Question 17:

(i) How many lakhs make a million?
(ii) How many lakhs make a billion?

Answer:

(i) Ten lakhs make a million.
(ii) Ten thousand lakhs make a billion.

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Question 18:

What is the smallest 3-digit number with unique digits?

Answer:

The smallest three-digit number with unique digits is 102.

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Question 19:

What is the largest 5-digit number with unique digits?

Answer:

The largest five-digit number with unique digits is 98,765.

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Question 20:

Write the smallest 3-digit number which does not change if the digits are written in reverse order.

Answer:

The smallest three-digit number that does not change if the digits are written in reverse order is 101.

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Question 21:

How many different 3-digit numbers can be formed by using the digits 0,2,5 without repeating any digit in the number?

Answer:

The three-digit numbers formed using the digits 0, 2 and 5 (without repeating any digit in the number) are 250, 205, 502 and 520.
Therefore, four such numbers can be formed.

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Question 22:

Find the difference between the number 279 and that obtained on reversing its digits.

Answer:

The number obtained on reversing 279 = 972

Difference = 972 − 279 = 693
Thus, the difference between 279 and that obtained on reversing its digits is 693.

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Question 23:

Form the largest and smallest 4-digit numbers using each of digits 7,1,0,5 only once.

Answer:

The largest and smallest four-digit numbers formed using 7, 1, 0 and 5 are 7,510 and 1,057.

 



Page No 1.7:

Question 24:

Write all possible 3-digit numbers using the digits 6,0,4 when

(i) repetition of digits is not allowed
(ii) repetition of digits is allowed

Answer:

(i) 604, 640, 460, 406
(ii) 666, 664, 646, 660, 606, 600, 644, 640, 604, 444, 466, 440, 446,464, 400, 404, 406, 460



Page No 1.9:

Question 1:

Put the appropriate symbols (<,>) in each of the following boxes:

(i) 102394      99887
(ii) 2507324      2517324
(iii) 3572014      10253104
(iv) 47983505      47894012

Answer:

(i) 1,02,394 > 99,887
(ii) 25,07,324 
< 25,17,324
(iii) 35,72,014 < 1,02,53,104
(iv) 4,79,83,505 > 4,78,94,012

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Question 2:

Arrange the following numbers in ascending order:

(i) 102345694, 8354208, 6539542, 63547201, 12345678
(ii) 1808090, 1808088, 181888, 190909, 16060666

Answer:

(i) 65,39,542, 83,54,208, 1,23,45,678, 6,35,47,201, 10,23,45,694

(ii) 1,81,888, 1,90,909, 18,08,088, 18,08,090, 1,60,60,666 

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Question 3:

Arrange the following numbers in descending order:

(i) 56943300, 56943201, 5695440, 56944000, 5694437
(ii) 1020216, 1020308, 1021430, 893245,893425

Answer:

(i) 5,69,44,000, 5,69,43,300, 5,69,43,201, 56,95,440, 56,94,437
(ii) 10,21,430, 10,20,308, 10,20,216, 8,93,425, 8,93,245



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