Futility Closet

“Lightning Addition”: Solution

Posted in Puzzles, Science & Math by Greg Ross on September 22nd, 2008

Solution to Lightning Addition:

Gauss included 0 in the series and rearranged the terms into 50 pairs, each of which totals 100:

100 + 0
99 + 1
98 + 2
etc.

The 50 pairs together make 5000, which, when added to the unpaired central number, 50, gives 5050, the correct sum.