Math lesson plan · 6th grade (Year 7 in England) · 45 minutes
Divide mixed numbers
Fractions
CCSS 6.NS.A.1England: KS3 Number
Objective and success criteria
Students will: Divide 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: Multiply mixed numbers; Divide fractions by 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 · 5 min
- Quick retrieval from earlier learning (Multiply mixed numbers; Divide fractions by fractions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Work out 1 2/5 × 4. Give a mixed number or fraction in simplest form. → 28/5 (5 3/5)Prompt: Write the mixed number as an improper fraction.
- 1/3 ÷ 3/4 = ? Give your answer in simplest form. → 4/9Prompt: Dividing by a fraction is the same as multiplying by its reciprocal.
- Work out 1 1/4 × 1 2/3. Give a mixed number or fraction in simplest form. → 25/12 (2 1/12)Prompt: Change both mixed numbers to improper fractions.
Hook · 5 min
- Cut a pizza or a strip of paper unevenly and ask whether the pieces are really halves or quarters.
- Share the objective: Divide mixed numbers. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Work out 4 1/4 ÷ 3. Give a mixed number or fraction in simplest form.
- Step 1: 17/4 × 1/3 = 17/12
- Step 2: = 1 5/12
- Answer: 17/12 (1 5/12)
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Work out 2 2/3 ÷ 4. Give a mixed number or fraction in simplest form. → 2/3Prompt: Write the mixed number as an improper fraction.
- Work out 3 1/4 ÷ 2 1/3. Give a mixed number or fraction in simplest form. → 39/28 (1 11/28)Prompt: Change both to improper fractions.
You do: independent practice · 10 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A trail is 8 3/4 km long. Marker posts are placed every 1 3/4 km, starting from the beginning. How many equal sections does this make? → 5Prompt: Divide the total length by the section length.
- Work out 1 1/2 ÷ 1 1/2. Give a mixed number or fraction in simplest form. → 1Prompt: Change both to improper 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: Multiply mixed numbers.
- 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-6.
Free lesson plan from eurekami.com/lesson-plan-builder