Long Multiplication: 100 × 80

"Long Multiplication Calculator" Calculator

Multiplicand (number to be multiplied)

Multiplier (number to multiply by)

What is 100 × 80?

Answer

100 × 80 = 8,000

100 × 80 and 80 × 100 are the same product — the order of the factors never changes the answer, only the working. Below, 100 is multiplied by 80 in a column, digit by digit.

100 × 80 in a Column

The multiplicand goes on top, the multiplier underneath, both aligned on the right. Only one digit of the multiplier is not zero, and it stands for 80, so there is a single partial product and the answer goes straight under the line.

  100
×  80
 8000
100 × 80 = 8,000

Step-by-Step Solution

Step 1: The last digit of the multiplier is 0, so this partial product is 0 and adds nothing to the total.

Step 2: The next digit of the multiplier is 8, and it stands for 80: 100 × 80 = 8,000.

  • 0 × 8 = 0. Write 0.
  • 0 × 8 = 0. Write 0.
  • 1 × 8 = 8. Write 8.

100 × 80

=

8,000

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 8,000 ÷ 80 = 100 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.

100 × 80 is a number, not an area. If those are the sides of a room in feet, the answer is 8,000 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 100 × 80? (The answer is: 8,000). Enter the multiplicand (e.g. '100') and the multiplier (e.g. '80') and hit the button. The order of the two numbers does not matter — 100 × 80 and 80 × 100 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 100

MultiplicationProduct
100 × 5500
100 × 6600
100 × 7700
100 × 8800
100 × 9900
100 × 101,000
100 × 111,100
100 × 121,200
100 × 151,500
100 × 161,600
100 × 202,000
100 × 252,500
100 × 303,000
100 × 404,000
100 × 505,000
100 × 606,000
100 × 757,500
100 × 808,000
100 × 909,000
100 × 10010,000

FAQ

What is 100 × 80?

100 × 80 = 8,000

Is 100 × 80 the same as 80 × 100?

Yes. Multiplication is commutative, so both come to 8,000. Only the working differs: this page multiplies by 80, which gives a single partial product.

How do you check that 100 × 80 = 8,000?

Divide the product back by one of the factors: 8,000 ÷ 80 = 100 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 100 × 80?

Only one of them counts: every other digit of 80 is a zero and contributes nothing, so the work comes down to 100 × 80 = 8,000, with nothing left to add.

See Also