What is the sum of the first 50 natural numbers? how to solve it without adding 50 digits?

Look at the first one and the last one:                  1 + 50 = 51
Look at the second one and the second-last one:  2 + 49 = 51
Look at the third one and the third-last one:           3 + 48 = 51

Every pair you construct in this way adds up to 51 .

There are ( 50/2 ) = 25 pairs.

They all add up to ( 25 pairs ) x ( 51 per pair ) = 1,275