Can you do 1 + 3 + 5 + 7 + ... + 99 in your head And how?
Guest 12 mins ago
Can you do 1 + 3 + 5 + 7 + ... + 99 in your head And how
There is a formula to solve this.
SUM= n/2(a+L)
a is the first number =1
L is the last number =99
n is the number of numbers = 50
So
Sum=25×100=2500
Sorry....I initially misread the question.....
There will be 25 pairs of numbers that will sum to 100, thusly.....
[99 + 1], [ 97 + 3], [ 95 + 5], etc.
So.....the sum is just 2500
1+99=100
3+97=100
5+95=100
7+93=100...
Thanks guest,
I like your method better than my one.
