Wyoming Math 4.NF.3c

Math4th GradeNumber and Operations - Fractions

The Standard

Understand a fraction a/b with a > 1 as a sum of unit fractions (1/b). Add and subtract mixed numbers with like denominators by replacing each mixed number with an equivalent fraction, and/or by using properties of addition and the relationship between addition and subtraction.

2023 Wyoming Mathematics Content and Performance Standards · Build fractions from unit fractions by applying and extending previous understandings of operations on whole numbers (limited to denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100).

Teacher's field guide

What This Standard Means

What Students Need to Do: Students show fractions as sums of equal-sized pieces, such as 3/4 = 1/4 + 1/4 + 1/4. They add and subtract mixed numbers with matching denominators by rewriting them as fractions or working with the whole numbers and fractional parts. They regroup a whole when needed.
What Mastery Looks Like: A student can use a sketch to show why 2 1/4 equals 9/4. They can solve 3 1/4 − 1 3/4 = 1 1/2 and show where the extra fourths came from.
Common Misconceptions: Students may add denominators and write 1/4 + 2/4 = 3/8. When subtracting, they may subtract the smaller fractional part from the larger one without regrouping a whole.
How to Assess It: Exit ticket: Solve 3 1/4 − 1 3/4. Use a drawing or equivalent fractions to show how you handled the fourths.

Lesson moves

Ways to Teach It

Use fraction strips to model 3 1/4 − 1 3/4, trading one whole for four fourths before removing pieces.
Ask students to draw 3 1/4 and write two sentences explaining why it equals 13/4.
Put 2 3/4 + 1 2/4 and 3 1/4 − 1 3/4 on cards, then have pairs match them to answer cards.
Show a recipe needing 2 3/4 cups of flour and a bag holding 4 1/4 cups; ask how much flour remains.

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