Math lesson plan · 6th grade (Year 7 in England) · 45 minutes
Add and subtract multi-digit decimals
Decimals and percentages
CCSS 6.NS.B.3England: KS3 Number
Objective and success criteria
Students will: Add and subtract multi-digit decimals.
- 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 decimals
Leads to: the next skill in this area.
Materials: Place value chart with tenths and hundredths, Hundred squares, Number lines, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Add and subtract decimals). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 23 + 92.14 = ? → 115.14Prompt: Line up the decimal points.
- 9.6 − 9.2 = ? → 0.4Prompt: Line up the decimal points and fill gaps with zeros.
- 73 + 69.65 = ? → 142.65Prompt: Line up the decimal points.
Hook · 5 min
- Show two prices or race times with decimals and ask which is bigger, then why.
- Share the objective: Add and subtract multi-digit decimals. 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 205.04 + 4.093.
- Step 1: 205.04 + 4.093 = 209.133
- Answer: 209.133
- 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 346.11 + 6.824. → 352.934Prompt: Line up the decimal points.
- Work out 61 − 8.19. → 52.81Prompt: Write 61 as 61.00.
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.
- Work out 647.02 + 8.778. → 655.798Prompt: Line up the decimal points.
- Work out 173 − 134.35. → 38.65Prompt: Write 173 as 173.00.
Watch out for
- Thinking 0.45 is bigger than 0.5 because 45 is bigger than 5.
- Moving the digits the wrong way when multiplying or dividing by 10.
Support and stretch
Support
- Review first: Add and subtract decimals.
- Use concrete materials: place value chart with tenths and hundredths.
- 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