When you work with numbers, there are sometimes rules that you need to follow. Sometimes it's important to know how to add things up, or subtract, or split things into fractions. With math, there is a special way to figure out things like this, and it's called an integral.
An integral is a type of equation that you use to figure out how different parts of a math problem add up. For example, if you have a range of numbers from 2 to 10, an integral can figure out the sum of all those numbers.
A table of integrals is a chart that lists the equation and the solution for a variety of different math problems. So if you need to solve a problem, you can look at the table, find the equation and then find the answer right away.