How much must be added to 2 times of 5 7 to get 3 . Let us calculate.

We need to find, how much must be added to 2 times of 5 7 to get 3 . Let the unknown number be x . Now, 10 7 + x = 3 ⇒ 10 + 7 x 7 = 3 ⇒ 10 + 7 x = 21 ⇒ 7 x = 21 - 10 = 11 ⇒ x = 11 7 ⇒ x = 1 4 7 Hence, the unknown number is 11 7 or 1 4 7 .

What must be multiplied with 5 7 to get 4 . Let us calculate.

We need to find, what must be multiplied with 5 7 to get 4 . Let the unknown number be x . Now, 5 7 × x = 4 ⇒ 5 x = 28 ⇒ x = 28 5 or 5 3 5 Hence, the unknown number is 28 5 or 5 3 5 .

2 3 , 4 5 and 2 3 × 4 5 - Let's calculate which one of these is of the least value.

Given, 2 3 , 4 5 and 2 3 × 4 5 Now, we need to calculate which one of these is greatest. The product of two given fractions is a fraction whose numerator is the product of the numerators of the given fractions and whose denominator is the product of the denominators of the given fractions. Then, 2 3 × 4 5 = 8 15 To compare given fractions 2 3 , 4 5 and 8 15 make their denominators same. That is, LCM of denominators 3 , 5 and 15 is 15 . Now, 2 3 × 5 5 = 10 15 , 4 5 × 3 3 = 12 15 If the denominators are the same, then the fraction with the smaller numerator is the smaller fraction. Then, here 8 15 has the least value. Hence, 2 3 × 4 5 has the least value among 2 3 , 4 5 and 2 3 × 4 5 .

5 2 , 7 3 and 5 2 × 7 3 : Calculate which one of these is greatest.

Given, 5 2 , 7 3 and 5 2 × 7 3 Now, we need to calculate which one of these is greatest. The product of two given fractions is a fraction whose numerator is the product of the numerators of the given fractions and whose denominator is the product of the denominators of the given fractions. Then, 5 2 × 7 3 = 35 6 To compare given fractions 5 2 , 7 3 and 35 6 make their denominators same. That is, LCM of denominators 2 , 3 and 6 is 6 Now, 5 2 × 3 3 = 15 6 , 7 3 × 2 2 = 14 6 If the denominators are the same, then the fraction with the greater numerator is the greater fraction. Then, here 35 6 is the greatest fraction. Hence, 5 2 × 7 3 is the greatest among 5 2 , 7 3 and 5 2 × 7 3 .

E M B I B E

GANITPRABHA (MATHEMATICS TEXT BOOK) CLASS 7>Chapter 1 - Revision of Previous Knowledge>Let's do ourselves

West Bengal Board Solutions for Chapter: Revision of Previous Knowledge, Exercise 1: Let's do ourselves

Author:West Bengal Board

West Bengal Board Mathematics Solutions for Exercise - West Bengal Board Solutions for Chapter: Revision of Previous Knowledge, Exercise 1: Let's do ourselves

Attempt the practice questions on Chapter 1: Revision of Previous Knowledge, Exercise 1: Let's do ourselves with hints and solutions to strengthen your understanding. GANITPRABHA (MATHEMATICS TEXT BOOK) CLASS 7 solutions are prepared by Experienced Embibe Experts.