Question

How do i do this? 1+3+5+7+...+101

Answer 1

Total numbers from pattern=51
First number+last number is 1+101=102
second number+second last number is 3+99=102.
This means that we can form pairs that make up 102.
Number of pairs=50/2=25
The remaining middle number is 26
Total value of pair=25×102
Total sum of pattern=25×102+26=

Answer 2

Hello,

Number of terms in 1+3+5+7+...+101
nb=(101-1)/2+1=51

Sum=((1+101)*51)/2=51²=2601