CCSS.Math.Content.4.NF.B
The standard
Build fractions from unit fractions by applying and extending previous understandings of operations on whole numbers.
Common Core State Standards for Mathematics
What this standard means
Students need to see fractions as numbers made from unit pieces, then use that idea to add, subtract, and multiply fractions by whole numbers. They should connect models, number lines, equations, and word problems, not treat fractions as symbols to follow rules with.
Mastery looks like explaining why 3/8 is three copies of 1/8, why 2/5 + 1/5 makes 3/5, and why 4 × 2/6 means four groups of 2/6. Students often get stuck adding denominators, losing track of the whole, or mixing up the number of parts with the size of each part.
Ways to teach it
- Give pairs fraction strips and ask them to build 5/6 in three different ways using unit fraction pieces.
- Prompt students: Write a story problem for 3 × 2/8, then draw a model that matches your story.
- Show four fraction equations on exit tickets and ask students to circle the one with an error and fix it.
- Use a recipe card and ask students how much flour is needed if three batches each use 2/3 cup.
Plan a lesson for CCSS.Math.Content.4.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.5.NF.B.7
Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions.
- 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.