CCSS.Math.Content.5.NF.A
The standard
Use equivalent fractions as a strategy to add and subtract fractions.
Common Core State Standards for Mathematics
What this standard means
Students need to add and subtract fractions with unlike denominators by renaming fractions into equivalent forms. They should know that the denominator names the size of the pieces, so pieces must be the same size before adding or subtracting. They also need to handle mixed numbers, regroup when needed, and simplify answers when reasonable.
Mastery looks like choosing a common denominator, making accurate equivalent fractions, combining numerators, and explaining why the answer makes sense. Students often get stuck adding denominators, picking huge common denominators, forgetting to change the numerator, or borrowing from a whole number in mixed-number subtraction.
Ways to teach it
- Use fraction strips to model 1/2 plus 1/3, then have students record the matching number sentence with sixths.
- Ask students to explain which is larger, 3/4 plus 1/6 or 2/3 plus 1/4, using words and numbers.
- Give three problems on sticky notes, including one mixed-number subtraction with regrouping, and sort responses by error type.
- Use a recipe card and ask students to find the total cups of two ingredients with different fractional amounts.
Plan a lesson for CCSS.Math.Content.5.NF.A
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Related standards
- CCSS.Math.Content.3.NF.A.3b
Recognize and generate simple equivalent fractions, e.g., 1/2 = 2/4, 4/6 = 2/3). Explain why the fractions are equivalent, e.g., by using a visual fraction mode...
- CCSS.Math.Content.5.NF.A.1
Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce...
- CCSS.Math.Content.4.NF.B.3d
Solve word problems involving addition and subtraction of fractions referring to the same whole and having like denominators, e.g., by using visual fraction mod...
- CCSS.Math.Content.4.NF.B.3c
Add and subtract mixed numbers with like denominators, e.g., by replacing each mixed number with an equivalent fraction, and/or by using properties of operation...