You can multiply numbers in several cases.
In general, if there are \(x\) additional things for every one of \(y\) other things, then there are \(xy\) altogether.
What?! This is just like saying “If each apple costs \($3\), and you need to buy five apples, the total cost would be \($3 \times 5 = $15\)”. Simple, if you have thirty additional people for every one class, and there are seven classes, you will have 210 people altogether.
This easy, simple, yet powerful thinking is the key to many problems.
Let’s move on to the key examples of multiplication.