Question

Find the value of the following by suitable rearrangement. Mention the

property used.
a. 25 x 679 x 4
b. 2917 x 102 - 2917 x 2

Answer 1

(a) 67900

(b) 291700

Explanation:

(a) 25 x 679 x 4

Rearrange the terms starting with the smallest

4 x 25 x 679

The property used here is the commutative property of multiplication which states that the order in which these numbers are multiplied does not matter.

Now solve

4 x 25 x 679 = 67900

(b) 2917 x 102 - 2917 x 2

Factor out the common terms

2917(102 - 2)

Using the distributive property which states that when a number is multiplied by the sum or difference of two numbers, the result is the same as multiplying each of the two numbers by the number and then adding or subtracting the products.

Now solve

2917(102 - 2) = 2917(100)

= 291700