9 times 9 is 81. In symbols: 9 × 9 = 81 (9 squared).
9 × 9 means adding 9 to itself 9 times: 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 = 81.
9, 18, 27, 36, 45, 54, 63, 72, 81. The 9th multiple of 9 is 81.
9 × 9 = 9 × 4 + 9 × 5 = 36 + 45 = 81.
81 ÷ 9 = 9
81 is odd and a perfect square. Prime factorization: 3 × 3 × 3 × 3.
| Multiplication | Answer |
|---|---|
| 8 × 9 | 72 |
| 9 × 10 | 90 |
| 9 × 11 | 99 |
| 7 × 9 | 63 |
See also: factors of 81 · 9 squared.
Other numbers? Browse the multiplication table, the squares and cubes or the exponent calculator.