Q5 of 119 Page 45

Express 100 as the sum of 10 odd numbers

We know that,

Sum of first n odd numbers = n2


Expressing 100 as a sum of 10 odd numbers


100 = (10)2


n = 10


100 = 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19


More from this chapter

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4

Without adding, find the sum:

(i) (1 + 3 + 5 + 7 + 9 + 11 + 13)

(ii) (1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19)

(iii) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23)

 5

Express 81 as the sum of 9 odd numbers

 6

Write a Pythagorean triplet whose smallest member is:

(i) 6 (ii) 14 (iii) 16 (iv) 20

 7

Evaluate:

(i) (38)2 - (37)2 (ii) (75)2 - (74)2


(iii) (92)2 - (91)2 (iv) (105)2 - (104)2


(v) (141)2 -(140)2 (vi) (218)2 - (217)2