Chapter 3: Playing with Number
Chapter 4:Basic Gemetrical Idea
Chapter 5:Understanding Elementry Shapes
Whole Number
(a)728 × 101
= 728 × (100 + 1)
= 728 × 100 + 728 × 1
= 72800 + 728
= 73528
(b)5437 × 1001
= 5437 × (1000 + 1)
= 5437 × 1000 + 5437 × 1
= 5437000 + 5437
= 5442437
(c)824 × 25
= 824 × 25
=824× (20+5)
=824 × 20 +824 × 5
=16480+4120
= 20600
(d)4275 × 125
= 4275 × (100+20+5)
= 4275 × 100 + 4275 × 20 + 4275 × 5
= 427500+ 85500+21375
= 534375
(e) 504 × 35
= (500 + 4) × 35
= 500 × 35 + 4 × 35
= 17500 + 140
= 17640