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Multiplying Fractions Calculator

Enter two fractions, press Calculate, and this fraction multiplication calculator shows the product along with every step that got there.

Multiplication is the friendliest of the four fraction operations, because it is the only one that does not care about denominators. You do not have to find a common denominator, you do not have to rewrite anything first, and the order of the two fractions makes no difference to the answer. You multiply straight across: numerator times numerator on the top, denominator times denominator on the bottom. What trips most people up is not the multiplying, it is the two things that happen around it. First, simplifying: a product like 6/20 is correct but nobody wants to see it, so it has to come down to 3/10, and forgetting that step costs marks. Second, the shortcut called cancelling, where a factor on the top of one fraction and the bottom of the other cancel out before you multiply, which keeps the numbers small enough to do in your head.

This calculator handles all of that. It multiplies the fractions you type in, reduces the answer to lowest terms, converts it to a mixed number when the result is bigger than 1, and prints the working so you can compare it against what you did on paper. Whole numbers work too: put the whole number on top and 1 underneath. If you want to see the answer as a shaded diagram instead of a number, use the View Visually button after any calculation.

Worked example: 3/4 × 2/5

  1. Multiply the numerators. 3 × 2 = 6, so the top of the answer is 6.
  2. Multiply the denominators. 4 × 5 = 20, so the bottom of the answer is 20.
  3. Write the product. 3/4 × 2/5 = 6/20.
  4. Simplify. The greatest common factor of 6 and 20 is 2, so divide both by 2: 6/20 = 3/10.
  5. Sanity check. 3/4 is 0.75 and 2/5 is 0.4. Multiplying gives 0.3, and 3/10 is 0.3, so the answer holds up.

The same problem with cancelling first: the 2 on top of 2/5 and the 4 on the bottom of 3/4 share a factor of 2. Cancel it to get 3/2 × 1/5, then multiply: 3/10. Same answer, smaller numbers, no simplifying at the end.

A second example with a whole number: 5/6 × 4

  1. Rewrite the whole number as a fraction: 4 becomes 4/1.
  2. Multiply the numerators: 5 × 4 = 20.
  3. Multiply the denominators: 6 × 1 = 6.
  4. The product is 20/6.
  5. Simplify: 20 and 6 share a factor of 2, so 20/6 = 10/3.
  6. Convert to a mixed number: 10/3 = 3 1/3, because 3 goes into 10 three times with 1 left over.

Notice the answer got bigger this time. That is because 4 is more than 1. Multiplying by anything greater than 1 grows the fraction, and multiplying by anything less than 1 shrinks it.

For students

Check homework answers and read the steps to find exactly where your own working went off track.

For teaching cancelling

Run the same problem with and without cancelling to show a class that both routes land on the same simplified answer.

For quick answers

Recipes, measurements, and scale drawings all need a fraction of a fraction. Type it in and get the reduced result.

Frequently Asked Questions

Common questions about multiplying fractions

Multiply the two numerators to get the new numerator, multiply the two denominators to get the new denominator, then simplify. For 3/4 × 2/5 that is (3×2)/(4×5) = 6/20, which reduces to 3/10. You never need a common denominator when multiplying.

Write the whole number over 1 and multiply as usual. For 5/6 × 4, use 4/1: (5×4)/(6×1) = 20/6 = 10/3, or 3 1/3 as a mixed number. In this calculator, type the whole number as the numerator and 1 as the denominator.

Either works and both give the same answer. Cancelling first keeps the numbers small: in 2/3 × 3/5 the 3 on top and the 3 on the bottom cancel, leaving 2/1 × 1/5 = 2/5. Multiplying first gives 6/15, which also reduces to 2/5.

Multiplying by a fraction less than 1 means taking a part of something, so the result shrinks. Half of 3/4 is 3/8, which is smaller than 3/4. If both fractions are less than 1, the answer is always smaller than either of them. If one fraction is improper (bigger than 1), the answer grows instead.