Lesson 1 of 15
A number you can draw as a square
Show on a big screenA tiler fixes floor tiles. His patch of floor is 7 tiles across. It has 7 rows. How many tiles is that?
Step 1 of 4
- A block, 7 tiles across and 7 tiles down.
- Top row: 7 tiles.
- Left column: 7 tiles.
- 7 × 7 = 49 tiles.
The patch has 49 tiles. Seven rows of 7 tiles make 7 × 7 = 49.
Rule: A square number is the tile count of a square. The same number of tiles go across as down.
We write 7 rows of 7 as 7². We say seven squared. The small raised 2 says two 7s are multiplied.
| Side | Written | Tiles |
|---|---|---|
| 1 | 1² | 1 |
| 2 | 2² | 4 |
| 3 | 3² | 9 |
| 4 | 4² | 16 |
| 5 | 5² | 25 |
| 6 | 6² | 36 |
| 7 | 7² | 49 |
| 8 | 8² | 64 |
| 9 | 9² | 81 |
| 10 | 10² | 100 |
| 11 | 11² | 121 |
| 12 | 12² | 144 |
| 13 | 13² | 169 |
| 14 | 14² | 196 |
| 15 | 15² | 225 |
The side need not be a whole number. A square of side 2.5 has area 2.5 × 2.5 = 6.25. That is an area, not a square number. A square number is a whole number of tiles in a square. It needs a whole side.
Slide the side. Watch the tiles fill in.
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Try the lab to finish this lesson.