Trade Math · Fractions

Fractions on the test

Add, subtract, multiply, and divide on paper, no calculator.

Cheat sheet

  • Add or subtract: get a common denominator, then add or subtract the numerators. Denominator stays the same.
  • Multiply: numerator × numerator, denominator × denominator. Then reduce.
  • Divide: invert the second fraction and multiply. ("Keep, change, flip.")
  • Mixed numbers: convert to improper fractions before operating, then convert back at the end.
  • Always reduce to lowest terms as the last step.

Example: 1/4 + 3/8

Common denominator is 8. Convert 1/4 to 2/8. Then 2/8 + 3/8 = 5/8.

2/8+3/8=5/8

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