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Q.2: Find the product by suitable rearrangement: ( NCERT Ex-2.2)

(f) 125 × 40 × 8 × 25

Sol: 125 × 40 × 8 × 25

= (125 × 8) × (40 × 25)

= 1000 x 1000

= 1000000

 Distributive Property of Multiplication over addition and subtraction.

If 10, 5 and 4 are three whole numbers, then distributive property of multiplication over addition is
10 × (5 + 4) = (10 × 5) + (10 × 4), similarly, the distributive property of multiplication over subtraction is
10 × (5 - 4) = (10 × 5) - (10 × 4)

Some more examples:

Q.3: Find the value of the following ( NCERT Ex-2.2)

(c) 81265 × 169 – 81265 × 69

= 81265 × (169 – 69)

= 81265 × 100

= 81,26,500

(d) 3845 × 5 × 782 + 769 × 25 × 218

= 19225×782+19225×218

=19225 × (782 + 218)

=19225 × 1000

=1,92,25,000

Q.4: Find the product using suitable properties. ( NCERT Ex-2.2)

(a) 738 × 103

= 738 × 103 = 738 × (100 + 3)

= (738 × 100) + (738 × 3) [By the distributive property of multiplication over addition]

= 73800 + 2214 = 76014

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