Fractions: watch it solved step by step

Add, subtract, multiply, divide and simplify fractions, with bars that show why. Level: KS3 / GCSE. Type any problem of this kind and the Lab works it out and animates every move, with a plain-words explanation of why.

Worked example: 3/4 - 1/6

  1. The sum. To subtract fractions the pieces must be the same size — the denominators must match.
  2. Find the common denominator: 12. List the multiples of each denominator. The first number in both lists is the lowest common denominator: 12.
  3. Make equivalent fractions. Multiply the top and bottom of each fraction by the same number to get denominator 12: 34 by 3; 16 by 2.
  4. Subtract the numerators. The pieces are the same size, so just subtract how many there are. The denominator stays 12.
  5. Already in simplest form. No number greater than 1 divides both the top and the bottom, so the fraction is already as simple as it can be.
  6. The answer. The answer is 7/12.

Answer: 7/12

Practise fractions with problems the Lab marks for you.

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