Long Multiplication: 20 × 15

"Long Multiplication Calculator" Calculator

Multiplicand (number to be multiplied)

Multiplier (number to multiply by)

What is 20 × 15?

Answer

20 × 15 = 300

20 × 15 and 15 × 20 are the same product — the order of the factors never changes the answer, only the working. Below, 20 is multiplied by 15 in a column, digit by digit.

20 × 15 in a Column

The multiplicand goes on top, the multiplier underneath, both aligned on the right. Each digit of the multiplier produces its own partial product, and the partial products are added up.

  20
× 15
 100
+200
 300
20 × 15 = 300

Step-by-Step Solution

Step 1: Multiply the multiplicand by the last digit of the multiplier, 5: 20 × 5 = 100.

  • 0 × 5 = 0. Write 0.
  • 2 × 5 = 10. Write 0 and carry 1.
  • No digits are left, so the carried 1 is written in front: the partial product is 100.

Step 2: The next digit of the multiplier is 1, and it stands for 10: 20 × 10 = 200.

  • 0 × 1 = 0. Write 0.
  • 2 × 1 = 2. Write 2.

100 + 200

=

300

Adding the partial products finishes the work: 20 × 15 = 300.

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 300 ÷ 15 = 20 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.

20 × 15 is a number, not an area. If those are the sides of a room in feet, the answer is 300 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.

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About "Long Multiplication Calculator" 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 20 × 15? (The answer is: 300). Enter the multiplicand (e.g. '20') and the multiplier (e.g. '15') and hit the button. The order of the two numbers does not matter — 20 × 15 and 15 × 20 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.

"Long Multiplication Calculator" Calculator

Multiplicand (number to be multiplied)

Multiplier (number to multiply by)

Products of 20

MultiplicationProduct
20 × 120
20 × 240
20 × 360
20 × 480
20 × 5100
20 × 6120
20 × 7140
20 × 8160
20 × 9180
20 × 10200
20 × 11220
20 × 12240
20 × 15300

FAQ

What is 20 × 15?

20 × 15 = 300

Is 20 × 15 the same as 15 × 20?

Yes. Multiplication is commutative, so both come to 300. Only the working differs: this page multiplies by 15, which gives 2 partial products.

How do you check that 20 × 15 = 300?

Divide the product back by one of the factors: 300 ÷ 15 = 20 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 20 × 15?

They are 100 + 200, and adding them gives 300.

See Also