Mathematics Part i Solutions Solutions for Class 7 Math Chapter 7 Shorthand Math are provided here with simple step-by-step explanations. These solutions for Shorthand Math are extremely popular among class 7 students for Math Shorthand Math Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Mathematics Part i Solutions Book of class 7 Math Chapter 7 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Mathematics Part i Solutions Solutions. All Mathematics Part i Solutions Solutions for class 7 Math are prepared by experts and are 100% accurate.
Page No 81:
Question 1:
Can you do these sums in your head?
(i) 38 + 63 + 37
(ii) 
(iii) 375 + 1.75 + 3.25
(iv) 85 + 96 + 15
(v)
Answer:
(i) 38 + 63 + 37
= 38 + (63 + 37)
= 38 + 100
= 138
(ii)
(iii) 375 + 1.75 + 3.25
= 375 + (1.75 + 3.25)
= 375 + 5
= 380
(iv) 85 + 96 + 15
= 85 + 15 + 96 (Using x + y = y + x)
= (85 + 15) + 96
= 100 + 96
= 96
(v)
Page No 82:
Question 1:
Can you do these in your head?
(i) (135 − 73) − 27
(ii)
(iii) (298 − 4.5) − 3.5
Answer:
(i) (135 − 73) − 27
= 135 − (73 + 27) {Using (x − y) − z = x − (y + z)}
= 135 − 100
= 35
(ii)
(iii) (298 − 4.5) − 3.5
= 298 − (4.5 + 3.5) {Using (x − y) − z = x − (y + z)}
= 298 − 8
= 290
Page No 83:
Question 1:
Some problems to do in head.
(i) (130 − 47) + 17
(ii)
(iii) (298 − 4.75) + 3.75
Answer:
(i) (130 − 47) + 17
= 130 − (47 − 17) {Using (x − y) + z = x − (y − z)}
= 130 − 30
= 100
(ii)
(iii) (298 − 4.75) + 3.75
= 298 − (4.75 − 3.75) {Using (x − y) + z = x − (y − z)}
= 298 − 1
= 297
Page No 87:
Question 1:
Mental math
(i) (83 × 12) + (17 × 12)
(ii)
(iii) (3.7 × 19) + (6.3 × 19)
(iv) (137 × 13) − (37 × 13)
(v)
Answer:
(i) (83 × 12) + (17 × 12)
= (83 + 17) × 12 {Using xz + yz = (x + y) z}
= 100 × 12
= 1200
(ii)
(iii) (3.7 × 19) + (6.3 × 19)
= (3.7 + 6.3) × 19 {Using xz + yz = (x + y) z}
= 10 × 19
= 190
(iv) (137 × 13) − (37 × 13)
= (137 − 37) × 13 {Using xz − yz = (x − y) z}
= 100 × 13
= 1300
(iv)
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