Long Multiplication: 15 × 9
What is 15 × 9?
Answer
15 × 9 and 9 × 15 are the same product — the order of the factors never changes the answer, only the working. Below, 15 is multiplied by 9 in a column, digit by digit.
15 × 9 in a Column
The multiplicand goes on top, the multiplier underneath, both aligned on the right. The multiplier has a single digit, so there is one partial product and the answer goes straight under the line.
| 1 | 5 | ||
| × | 9 | ||
| 1 | 3 | 5 |
Step-by-Step Solution
Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 15 × 9 = 135.
- 5 × 9 = 45. Write 5 and carry 4.
- 1 × 9 = 9, plus the carried 4 makes 13. Write 3 and carry 1.
- No digits are left, so the carried 1 is written in front: the partial product is 135.
15 × 9
=135
Check It, and What It Is Not
Check by dividing back. Multiplication and division undo each other, so 135 ÷ 9 = 15 must come out exactly, with no remainder.
Fractions are a different calculation. Both factors here are whole numbers; for 2/3 or 2 3/4 use the fraction multiplication calculator, which multiplies numerators and denominators separately.
15 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 135 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.
Related Calculations
See Also
- Long Division Calculator - Step-by-step long division with detailed explanation
- Multiplying Fractions Calculator - Multiply fractions, mixed numbers and whole numbers step by step
- Factors of a Number - List all Factors and Factor Pairs of a Number
- Greatest Common Factor - Find the Greatest Common Factor (GCF) of two numbers
- Least Common Multiple - Find the Least Common Multiple (LCM) of two numbers
<a href="https://calculat.io/en/number/long-multiplication/15--9">15 × 9 = 135 - Long Multiplication - Calculatio</a>