Multiplication is one of the four basic operations in arithmetic, along with addition, subtraction, and division. If you have a group of something, you use addition to add up the total number of things in the group. But if you have a group of GROUPS, you use multiplication to add up the total number across all the groups. For example, 5x3 is the measure for five groups, each containing three things. If you add up the things in all five groups, you get 15 total things. Multiplication can always give you these numbers as long as all the groups are the same size.
Multiplication is also used to measure the size of an area. If you have a rectangular desk, and you want to know how big its surface is, all you have to do is measure two of the sides and then multiply it together. So if it’s two feet wide and four feet long,.