Long Multiplication: 31 × 9

Long Multiplication Calculator
Multiplicand (number to be multiplied)
Multiplier (number to multiply by)

What is 31 × 9?

Answer

31 × 9 =
279

31 × 9 and 9 × 31 are the same product — the order of the factors never changes the answer, only the working. Below, 31 is multiplied by 9 in a column, digit by digit.

31 × 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.

  31
×  9
 279
31 × 9 = 279

Step-by-Step Solution

Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 31 × 9 = 279.

  • 1 × 9 = 9. Write 9.
  • 3 × 9 = 27. Write 7 and carry 2.
  • No digits are left, so the carried 2 is written in front: the partial product is 279.

31 × 9

=

279

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 279 ÷ 9 = 31 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.

31 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 279 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.

Related Calculations

See Also

Long Multiplication Calculator

This calculator multiplies two whole numbers the way it is done on paper: digit by digit, carrying where the column overflows, then adding the partial products together. For example, it can help you find out what is 31 × 9? (The answer is: 279). Enter the multiplicand (e.g. '31') and the multiplier (e.g. '9') and hit the button. The order of the two numbers does not matter — 31 × 9 and 9 × 31 are the same product — so either number can go on top. Fractions and mixed numbers belong to the fraction multiplication calculator, and the reverse operation is long division.
Recalculate with different values ↑

Products of 31

MultiplicationProduct
21 × 9189
22 × 9198
23 × 9207
24 × 9216
25 × 9225
26 × 9234
27 × 9243
28 × 9252
29 × 9261
30 × 9270
31 × 9279
32 × 9288
33 × 9297
34 × 9306
35 × 9315
36 × 9324
37 × 9333
38 × 9342
39 × 9351
40 × 9360

FAQ

What is 31 × 9?

31 × 9 = 279

Is 31 × 9 the same as 9 × 31?

Yes. Multiplication is commutative, so both come to 279. Only the working differs: this page multiplies by 9, which gives a single partial product.

How do you check that 31 × 9 = 279?

Divide the product back by one of the factors: 279 ÷ 9 = 31 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 31 × 9?

There is only one: the multiplier 9 has a single digit, so 31 × 9 = 279 is written straight under the line, with no addition step.

See Also