Square and cube numbers

For grown-ups: this lesson in words

Years 5 and 6 · Maths

Square and cube numbers: I can find square and cube numbers and write them with ² and ³.

1. Here are 3 rows of 3 blue tiles.

   Count the rows in 3s: 3, 6, 9.

   3 × 3 = 9

   The 9 tiles make one big square, so 9 is a square number.

   Picture: An array of 3 rows of 3 blue squares. The rows are counted in 3s: 3, 6 and 9.

2. Now 4 rows of 4 blue tiles.

   Count the rows in 4s: 4, 8, 12, 16.

   4 × 4 = 16

   The 16 tiles make a big square too. 16 is a square number.

   Picture: An array of 4 rows of 4 blue squares. The rows are counted in 4s: 4, 8, 12 and 16.

3. There is a short way to write 4 × 4.

   4² = 4 × 4 = 16

   4²: the small 2 means squared. We say four squared.

   A square number is a number times itself.

   Picture: An array of 4 rows of 4 blue squares.

4. Your turn: Here are 5 rows of 5 blue tiles. What is 5²?

   Picture: An array of 5 rows of 5 blue squares.

   Choose one:

   • 10
   • 25
   • 52

   Answer

   The answer: 25

   5² = 5 × 5 = 25

   Picture: An array of 5 rows of 5 blue squares. The rows are counted in 5s: 5, 10, 15, 20 and 25.

Words to know

square number:

A number times itself, like 3 × 3 = 9.

squared:

Times itself. The small 2 in 4² means 4 × 4.

cube number:

A number times itself, then times itself again, like 2 × 2 × 2 = 8.

cubed:

Times itself, then times itself again. The small 3 in 2³ means 2 × 2 × 2.