When we multiply two of the same numbers together, such as , we say that we are squaring the number. We can write it like this:
The raised 2 in is called an exponent.
Because , we write and we say, “5 squared is 25.”
When we multiply three of the same numbers together, such as , we say that we are cubing the number. We can write it like this:
Because , we write and we say, “4 cubed is 64.”
We also use an exponent for square units and cubic units.
- A square with a side length of 5 inches has an area of 25 in2.
- A cube with an edge length of 4 cm has a volume of 64 cm3.
To read 25 in2, we say “25 square inches,” just like before.
The area of a square with a side length of 7 kilometers is km2. The volume of a cube with an edge length of 2 millimeters is mm3.
In general, the area of a square with a side length of is , and the volume of a cube with an edge length of is .
