Question

Without actual addition, find the sum of: (i) 1 + 3 +5 + 7 + 9 + 11 + 13 (ii) 1 + 3+ 5 +7 +9 + 11 + 13 + 15

Answer 1

Step-by-step explanation:

1)1+3+5+7+9+11+13=7²(as if the as numbers are odd and corresponding then their sum is the square of the total number of digits)

1+3+5+7+9+11+13=49

2)1+3+5+7+9+11+13+15=8²=64

Answer 2

Answer:

Yeah... Here u goo

Step-by-step explanation:

Here a1 = 1

D = 2

Sn =?

N = 7

Here...we wanna find "Sn"

Sn = n/2 (2a + (n-1) d )

Substitute the formula

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