Square numbers
Do you know that there are numbers we call square numbers? Why do we
call them sqtiare numbers? Because they can be shown in the shape of a
square!
Remember, every number is macle out of ones. A number such as four
really stands for four ones. If you use four pennies (or buttons or
dots) to stand for the ones, you can arrange the pennies in the shape
of a square because four is a square number.
If you look at the squares of pennies shown below, you’ll see the first
five square numbers. There are two rows of two pennies each in the
number four. There are three rows of three pennies each in the number
nine. And so on, all the way up to six rows of six pennies each in the
square number thirty-six.
Now, how many rows of pennies would it
take to make the next square number? That’s right—seven rows of seven
pennies each make forty-nine, the next square number.
To make a square number, you just take any number and add it together as
many times as it is worth. In other words, if you take the number six
and add it together six times you get a square number—thirty-six.
When you add numbers together several times this way, you are
multiplying them. And that’s all that multiplication really is—a fast
way of adding a lot of numbers. So, a square number is simply a number
that’s made by multiplying any number by itself—two times two, three
times three, and so on. When you multiply a number by itself, this is
called “squaring” it.
