Question

6. Find the sum of each of the following without actual addition:
(0) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17
(ii) 11 + 13 + 15 + 17 + 19 + 21
(Hint: The required sum = (1 + 3 + 5 + ......+ 21) - (1 + 3 + 5 + .....+9))
(iii) 31 + 33 + 35 + 37 +39 +41
(iv) 2 + 6 + 10 + 14 + 18 + 22 + 26 + 30
(Hint: The required sum = 2 x (1 + 3 + 5 + .....+ 15)
(v) 18 + 224 26 + 30 + 34 + 38 +42 +46 + 50​

Answer 1

Answer:

(I) count the of numbers.

9 numbers.

= find the square of 9

=(9)^2

= 81 is the sum= answer

hope it helps