Page 27 - Start Up Mathematics_5

So, we write 1 in the blank space.

Continuing in this manner, we get all the missing digits.

TL L TTh Th H T O
3 7 8 6 7 1 5
+ 2 1 5 4 9 6 8

5 9 4 1 6 8 3

Properties of addition

1. Order commutative property

Two numbers can be added in any order. Their sum will remain the same.

For example, 17,624 + 38,715 = 38,715 + 17,624 = 56,339

2. Associative property
Three numbers can be added in any order. Their sum will remain the same.

For example, (2,48,015 + 1,76,240) + 93,148 = 2,48,015 + (1,76,240 + 93,148) = 5,17,403

3. Zero identity property
When 0 is added to a number, the sum is the number itself.

For example, 9,76,845 + 0 = 0 + 9,76,845 = 9,76,845

EXERCISE 2.1

1. Add the following numbers.

(a) 8,26,074; 17,03,21,462 and 9,16,34,195
(b) 9,24,16,317; 5,14,30,056; 10,21,96,987 and 79,34,680

(c) 15,36,24,740; 32,91,00,591; 7,85,09,024 and 79,34,680
(d) 10,00,00,054; 29,11,34,600; 31,41,26,999 and 47,65,108

(e) 9,63,45,174; 82,00,001; 7,00,68,198 and 99,064
(f) 18,34,268; 759; 8,92,163; 91,24,36,001 and 7,56,34,926

(g) 9,432; 15,706; 9,21,317; 85,30,100 and 2,00,65,915
2. Find the missing digits.

(a) C TL L TTh Th H T O

5 ? 7 ? 8 ? 0 4
+ ? 7 8 0 ? 7 2 ?
8 1 ? 7 3 8 ? 0

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