Adding Several Integers

A long sum of integers is worked like any long sum: left to right, one step per line. Take 6 + (-10) + 8 + (-1), which can also be written 6 - 10 + 8 - 1. First 6 + (-10) is -4, giving -4 + 8 - 1. Then -4 + 8 is 4, giving 4 - 1. Then 3.

There is a second route: gather the positives and the negatives. The positives 6 and 8 make 14. The negatives -10 and -1 make -11. Then 14 - 11 is 3. Both routes give the same answer because a sum can be added in any order, and the second one has only a single sign change at the end.

Either way, read each minus sign as belonging to the number after it. In 6 - 10 + 8 - 1 the numbers being added are 6, -10, 8 and -1. That is what lets you move them around, and it stops the slip of subtracting the 8 along with the 10.