Long Multiplication: 420 × 7
What is 420 × 7?
Answer
420 × 7 and 7 × 420 are the same product — the order of the factors never changes the answer, only the working. Below, 420 is multiplied by 7 in a column, digit by digit.
420 × 7 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 | 0 | ||
| × | 7 | |||
| 2 | 9 | 4 | 0 |
Step-by-Step Solution
Step 1: Multiply the multiplicand by the last digit of the multiplier, 7: 420 × 7 = 2,940.
- 0 × 7 = 0. Write 0.
- 2 × 7 = 14. Write 4 and carry 1.
- 4 × 7 = 28, plus the carried 1 makes 29. Write 9 and carry 2.
- No digits are left, so the carried 2 is written in front: the partial product is 2,940.
420 × 7
=2,940
Check It, and What It Is Not
Check by dividing back. Multiplication and division undo each other, so 2,940 ÷ 7 = 420 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.
420 × 7 is a number, not an area. If those are the sides of a room in feet, the answer is 2,940 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.
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/420--7">420 × 7 = 2,940 - Long Multiplication - Calculatio</a>