Fraction Math

What is a Fraction?

  • A fraction represents a part of a whole.

  • It has two parts:

    • Numerator (top number): how many parts you have

    • Denominator (bottom number): how many equal parts the whole is divided into

Adding Fractions

1. Same Denominator

  • Add the numerators, keep the denominator the same

2. Different Denominators

  • Find a common denominator (usually the least common multiple, LCM)

    • if its hard to figure out multiply the denominators together to find a common denominator

  • Rewrite each fraction with the new denominator

  • Add the numerators

key reminder: what you multiply the denominator by you HAVE to multiply the numerator by

Subtracting Fractions

  • Same rules as addition!

  • 1. Same Denominator

    • subtract the numerators, keep the denominator the same

    2. Different Denominators

    • Find a common denominator (usually the least common multiple, LCM)

      • if its hard to figure out multiply the denominators together to find a common denominator

    • Rewrite each fraction with the new denominator

    • subtract the numerators

  • Multiplying Fractions

    • Multiply straight across:

      • Numerator × numerator

      • Denominator × denominator

Dividing Fractions

  • Keep, Change, Flip

    1. Keep the first fraction

    2. Change ÷ to ×

    3. Flip the second fraction (reciprocal)

Improper Fractions ↔ Mixed Numbers

What is an Improper Fraction?

  • The numerator is bigger than denominator

What is a Mixed Number?

  • a number made up of a whole number and a fraction together.