Combine fractions and measurement
4th Grade Math practice: A water jug has 5 3/4 liters. After 2 1/4 liters are used, 1 2/4 liters are added. How much water is in the jug now. Part of extension: problem solving (Extension: Problem Solving).
~11 min
Use the same unit and same denominator before adding or subtracting fractional amounts.
Matching Denominators
3/8 shaded
To add or subtract fractions, the denominators must be the same so that the pieces you are counting have the same size. If the denominators are already the same, you just add or subtract the numerators while keeping the denominator the same.
💡 Think of denominators as labels for the size of the piece.