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Knowing Our Numbers

Do you know how many students are there in your class?

The number of students in your class would be a two-digit number or, at the maximum, a three-digit number. These are smaller numbers.

But if you are asked the number of students in your school, then it would be a bigger number.

The total number of students in a city would be a large number, i.e. at least a five-digit number.

And, if we count the total number of students in the whole country, then we would have to use very large numbers (like eight or nine-digit numbers). Therefore, here, we will learn about large numbers.

To understand a number, there are two most important things to know, face value and place value of each of its digits.

In a number, face value of each digit is the actual value of that digit and it never changes whether the number is written according to any numeral system.

Consider the number 3,69,821. In this number, face values of different digits are as follows:

Face value of 3 = 3

Face value of 6 = 6

Face value of 9 = 9

Face value of 8 = 8

Face value of 2 = 2

Face value of 1 = 1

Now, to understand the place value of digits of a large number and expansion of the number, let us go through the following video.

Thus, we can read the number 7,86,790 easily as "Seven lakh eighty six thousand seven hundred and ninety".

Similarly, we can write the numeral value of any given number.

Do you know we also have a relation between different place values?

Let us go through the following video, to understand the relation.

Thus, we must remember the following conversions which will be helpful in reading and writing numbers.

1 hundred = 10 tens

1 thousand = 10 hundreds = 100 tens

1 lakh = 100 thousands = 1000 hundreds

1 crore = 100 lakhs = 10,000 thousands

Let us now have a look at some examples to understand the concept better.

Example 1:

Write 6508927 in expanded form and write the place values and face values of underlined digits.

Solution:

The number 6508927 can be written in expanded form as follows:

6508927 = 6 × 1000000 + 5 × 100000 + 0 × 10000 + 8 × 1000 + 9 × 100 + 2 × 10 + 7 × 1

Place value of 7 = one

Face value of 7 = 7

Place value of 8 = thousand

Face value of 8 = 8

Place value of 5 = lakh

Face value of 5 = 5

Example 2:

Write the following numbers in words and answer the questions given below.

432079, 5601729 and 1794805

(1) Which is the smallest number?

(2) Which is the largest number?

(3) Arrange these numbers in ascending and descending order.

Solution:

4,32,079 = Four lakh thirty two thousand and seventy nine

56,01,729 = Fifty six lakh one thousand seven hundred and twenty nine

17,94,805 = Seventeen lakh ninety four thousand eight hundred and five

(1) 4,32,079 is the smallest number.

(2) 56,01,729 is the largest number.

(3) Therefore, the numbers in the ascendiā¦

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