Square numbers
A square number is what you get when you multiply a whole number by itself.
A square number is the answer when you multiply a whole number by itself. , so 25 is a square number. We write this as , said "five squared".
The name "square" is not random. If you arrange 25 dots into a grid, they make a perfect square that is 5 dots wide and 5 dots tall.
The first few square numbers are . It is well worth learning them up to by heart, because they pop up constantly in area, in mental arithmetic, and in later topics.
Notice the gaps between square numbers grow by the odd numbers: That neat pattern is a quick way to check you have the list right.
- A square number comes from multiplying a whole number by itself.
- means and is read 'five squared'.
- Square numbers fit exactly into square grids of dots.
- Learn them up to for fast mental work.