Home › Adventure Map › Subtraction › Subtracting Fractions
← Return to Adventure Map

Subtracting Fractions

The Hook

Slicing the pie.

What is it?

Finding the difference between two fractional parts.

Time Travel (History)

Ancient Egyptians used complex tables for this because they only liked fractions with a 1 on top (Unit Fractions).

Cheat Code

You can't subtract Apples from Oranges. Make the Bottoms Match.

Practice This Now!

The Field Guide

In Plain English: To subtract slices of pizza, the slices must be the same size. You can't subtract a 'half' from a 'quarter' directly. You have to turn the half into two quarters first.

In The Real World: Cooking. You have 3/4 cup of flour, you use 1/2 cup. How much is left?

How To Do It

  1. Check the denominators (bottoms).
  2. If different, find a Common Denominator (multiply them).
  3. Subtract the numerators (tops) ONLY.
  4. Keep the denominator the same.
  5. Simplify if possible.
⚠

Booby Trap!

Subtracting the bottoms! 3/4 - 1/4 is NOT 2/0. The bottom number just stays the same.

Real World Challenge
"You have 3/4 of a tank of gas. You use 1/4. What is left?"
The Logic: Bottoms match (4). Subtract tops: 3 - 1 = 2. Result: 2/4. Simplify to 1/2.

Training Drills

Common Denom
3 1 2 1 - - - = - = - 4 4 4 2
Bottoms stay 4.