Square of 4
4 squared equals 16. Squares appear in area calculations, the Pythagorean theorem, and statistics (variance uses squared distances).
Squares obey quiet rules. Divided by 9, a square only ever leaves 0, 1, 4 or 7 — 7 here. On the last digit, squares end only in 0, 1, 4, 5, 6 or 9, and 6 fits. Between its neighbors, 9 sits 7 below and 25 sits 9 above — the square ladder widens by exactly two at every step. Double the base and the square quadruples: 8² = 64, which is 4 × 16. Two anchors most worth memorizing in this range are 12² = 144 and 15² = 225 — the odd-step rule above is why knowing them pays off, because from any anchor the next square is one step along this page's ladder.
| Expression | Value |
|---|---|
| 4² | 16 |
Frequently asked questions
What is 4 squared?
4 squared is 16, because 4 × 4 = 16. The exponent 2 is why it is written 4².
What is 5 squared, next to 4²?
5² = 25, which is 9 more than 4² = 16. Each step up adds double the base plus one.
Where do squares show up in real problems?
Area of a square with side 4, distance in the Pythagorean theorem, and variance in statistics all use squared values.