Question

find the sum of the following numbers without actual adding 1 + 3 + 5 + 7+9+11+13+15+17
step by step explanation​

Answer 1

Answer:

$1 + 3 + 5 + 7+9+11+13+15+17$

Adding 1st number with last number, 2nd with 2nd last number and so on...

$18+18+18+18+9$

$18(4)+9$

$72+9$

$81$