Question

Find out the sum by suitable arrangement.
1 + 2 + 3 + 4 + 5 + 95 + 96 + 97 + 98 + 99

Answer 1

500

Explanation:

rearrange the sum as

(99 + 1) + (98 + 2) + (97 + 3) + (96 + 4) + (95 + 5)

= 100 + 100 + 100 + 1000 + 100

= 5 × 100

= 500

Answer 2

1 + 2 + 3 + 4 + 5 + 95 + 96 + 97 + 98 + 99. = 500