Class 1 of the third-grade expansion class of mathematics in Beijing Normal University is Gaussian summation.

Gauss and * * * have four formulas, namely: the last term is equal to the number of additions of the first term minus 1 multiple tolerance. The number of items is equal to the last item minus the first item divided by the tolerance plus 1. The first term is equal to the last term minus the number of terms and minus 1 times the tolerance. The sum is equal to the first term plus the last term multiplied by the number of terms and then divided by 2. Both are used for arithmetic progression summation.