Long Multiplication: 42 × 9
What is 42 × 9?
Answer
42 × 9 and 9 × 42 are the same product — the order of the factors never changes the answer, only the working. Below, 42 is multiplied by 9 in a column, digit by digit.
42 × 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.
| 4 | 2 | ||
| × | 9 | ||
| 3 | 7 | 8 |
Step-by-Step Solution
Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 42 × 9 = 378.
- 2 × 9 = 18. Write 8 and carry 1.
- 4 × 9 = 36, plus the carried 1 makes 37. Write 7 and carry 3.
- No digits are left, so the carried 3 is written in front: the partial product is 378.
42 × 9
=378
Check It, and What It Is Not
Check by dividing back. Multiplication and division undo each other, so 378 ÷ 9 = 42 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.
42 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 378 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.
Related Calculations
See Also
- Times Table Chart - Any number from 1 to 100, rows from ×1 to ×12
- 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/42--9">42 × 9 = 378 - Long Multiplication - Calculatio</a>