find the sum of the numbers from 1 to 200 inclusive

1 answer

There is a story that a famous German mathematician named Gauss was given this by his elementary teacher to keep the students busy in class.
They all started adding like crazy, but little Gauss just looked at it for a while, and quickly got the answer.

he added:
the first + last ---> 1+200 = 201
the 2nd + 2nd last --> 2 + 199 = 201
the 3rd + 3rd last --> 3 + 198 =201
ahhh, he said
aren't there just 100 of these?
so 100*201 = 20100