Math lesson plan · 4th grade (Year 5 in England) · 30 minutes
Add and subtract fractions with like denominators
Fractions
CCSS 4.NF.B.3England: Y4 FractionsEngland: Y5 Fractions
Objective and success criteria
Students will: Add and subtract fractions with like denominators.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Understand fractions a/b; Equivalent fractions
Leads to: Mixed numbers and improper fractions; Multiply a fraction by a whole number; Add and subtract fractions with unlike denominators
Materials: Fraction strips or a fraction wall, Paper strips to fold, Number lines, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Understand fractions a/b; Equivalent fractions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
Hook · 3 min
- Cut a pizza or a strip of paper unevenly and ask whether the pieces are really halves or quarters.
- Share the objective: Add and subtract fractions with like denominators. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: 3/5 − 2/5 = ?
- Step 1: 3 − 2 = 1
- Step 2: 3/5 − 2/5 = 1/5
- Answer: 1/5
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- 9/10 − 4/10 = ? → 5/10Prompt: Same denominators: subtract the numerators.
- Sam walked 2/4 of a mile to the park and then 1/4 of a mile to the library. How far did Sam walk in total? (Simplest form.) → 3/4Prompt: Add the two distances.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- 3/6 − 1/6 = ? → 2/6Prompt: Same denominators: subtract the numerators.
- Daniel walked 5/8 of a mile to the park and then 2/8 of a mile to the library. How far did Daniel walk in total? (Simplest form.) → 7/8Prompt: Add the two distances.
Watch out for
- Thinking a bigger denominator means a bigger fraction (1/8 > 1/4).
- Adding the denominators when adding fractions (1/2 + 1/3 = 2/5).
Support and stretch
Support
- Review first: Understand fractions a/b.
- Use concrete materials: fraction strips or a fraction wall.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Mixed numbers and improper fractions; Multiply a fraction by a whole number; Add and subtract fractions with unlike denominators.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-4.
Free lesson plan from eurekami.com/lesson-plan-builder