CCSS.Math.Content.5.NF.B
The standard
Apply and extend previous understandings of multiplication and division to multiply and divide fractions.
Common Core State Standards for Mathematics
What this standard means
Students need to see fraction multiplication as scaling and as finding part of a part, not just “multiply tops and bottoms.” They also need to divide whole numbers by unit fractions and unit fractions by whole numbers using models, equations, and story problems.
Mastery looks like drawing or explaining why an answer makes sense before calculating. Students can tell when a product should be smaller or larger. Common stuck points are treating every fraction problem the same, flipping the wrong number in division, and losing the meaning of the units.
Ways to teach it
- Use fraction strips or grid paper to model 2/3 of 3/4, then write the matching equation.
- Prompt students: How can multiplying by 1/2 make a number smaller, and when does multiplying make a number bigger?
- Give three problems and ask students to estimate first, draw one model, then solve: 4 x 2/3, 1/5 of 10, 3 ÷ 1/4.
- Use a recipe card and ask students to find half or triple amounts like 3/4 cup flour or 2/3 cup milk.
Plan a lesson for CCSS.Math.Content.5.NF.B
Generate a complete lesson plan aligned to this standard, with objectives, activities, and materials. Free, no account needed.
Related standards
- CCSS.Math.Content.5.NF.B.4
Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
- CCSS.Math.Content.7.NS.A.2
Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers.
- CCSS.Math.Content.6.NS.A
Apply and extend previous understandings of multiplication and division to divide fractions by fractions.
- CCSS.Math.Content.4.NF.B.4
Apply and extend previous understandings of multiplication to multiply a fraction by a whole number.