Question
By re-arranging the given numbers evaluate :
21 + 22 + 23 + 24 + 25 + 75 + 76 + 77 + 78 + 79
21 + 22 + 23 + 24 + 25 + 75 + 76 + 77 + 78 + 79
✓
Answer
21 + 22 + 23 + 24 + 25 + 75 + 76 + 77 + 78 + 79
= (21 + 79) + (22 + 78) + (23 + 77) + (24 + 76) + (25 + 75) (by associative law)
= 100 + 100+ 100+ 100 + 100 = 500
= (21 + 79) + (22 + 78) + (23 + 77) + (24 + 76) + (25 + 75) (by associative law)
= 100 + 100+ 100+ 100 + 100 = 500
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