Math lesson plan · 5th grade (Year 6 in England) · 30 minutes
Add and subtract mixed numbers
Fractions
CCSS 5.NF.A.1CCSS 4.NF.B.3.CEngland: Y6 Fractions
Objective and success criteria
Students will: Add and subtract mixed numbers.
- 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: Add and subtract fractions with unlike denominators; Mixed numbers and improper fractions
Leads to: the next skill in this area.
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 (Add and subtract fractions with unlike denominators; Mixed numbers and improper fractions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 2/3 + 2/5 = ? Give your answer in simplest form. → 16/15 (1 1/15)Prompt: You need a common denominator first.
- Write 1 1/2 as an improper fraction. → 3/2 (1 1/2)Prompt: How many pieces of size 1/2 are in 1 whole?
- 11/12 − 3/5 = ? Give your answer in simplest form. → 19/60Prompt: Find a common denominator.
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 mixed numbers. 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 1/6 + 2 5/6 = ? (Give a fraction in simplest form, or a mixed number like 3 1/4.)
- Step 1: 3 + 2 = 5
- Step 2: 1/6 + 5/6 = 6/6
- Step 3: 5 + 6/6 = 6
- Answer: 6
- 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.
- 3 3/4 + 3 1/4 = ? (Give a fraction in simplest form, or a mixed number like 3 1/4.) → 7Prompt: Add the whole numbers, then add the fractions.
- 7 1/8 − 3 7/8 = ? (Simplest form; a mixed number is fine.) → 13/4 (3 1/4)Prompt: 1/8 is smaller than 7/8: exchange one whole for 8/8.
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.
- 5 1/5 − 4 2/5 = ? (Simplest form; a mixed number is fine.) → 4/5Prompt: 1/5 is smaller than 2/5: exchange one whole for 5/5.
- 2 5/6 + 1 5/6 = ? (Give a fraction in simplest form, or a mixed number like 3 1/4.) → 14/3 (4 2/3)Prompt: Add the whole numbers, then add the fractions.
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: Add and subtract fractions with unlike denominators.
- 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
- 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-5.
Free lesson plan from eurekami.com/lesson-plan-builder