A sum is when a few groups of things are put all together. For example, there is one group of 2 carrots, one group of 3 carrots, and one group of 4 carrots. We sum them by sliding the groups all together, counting, and finding that there are 9 carrots all together. Thus the sum of 2 carrots, 3 carrots, and 4 carrots is 9 carrots. And those carrots can be replaced with anything; calculators, pencils, maple trees, planets, alternate realities, anything.

We denote the sum function by $+$. Thus if we wanted to denote a sum of two carrots, three carrots, and four carrots mathematically, we would write $2+3+4=9$. This article is a stub. Help us out by expanding it.