Math lesson plan · 5th grade (Year 6 in England) · 45 minutes
Multiply a decimal by a whole number
Decimals and percentages
CCSS 5.NBT.B.7England: Y6 Fractions (including decimals)
Objective and success criteria
Students will: Multiply a decimal by a whole number.
- 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 with different numbers of places; Multiply a three-digit number by a one-digit number
Leads to: Divide a decimal by a whole number; Decimal multiplication and division problems
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 with different numbers of places; Multiply a three-digit number by a one-digit number). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 68.9 + 3.983 = ? → 72.883Prompt: Line up the decimal points, not the last digits.
- 596 × 3 = ? → 1788Prompt: Multiply the hundreds, tens and ones separately.
- 5.88 − 3 = ? → 2.88Prompt: Write 3 as 3.00.
Hook · 5 min
- Show two prices or race times with decimals and ask which is bigger, then why.
- Share the objective: Multiply a decimal by a whole number. 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: 9.7 × 2 = ?
- Step 1: 97 × 2 = 194
- Step 2: 194 ÷ 10 = 19.4
- Answer: 19.4
- 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.
- 2.9 × 4 = ? → 11.6Prompt: Work out 29 × 4 first.
- A bus ticket costs $3.26. Zara buys 3 tickets. What is the total cost? → 9.78Prompt: Multiply 3.26 by 3.
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.
- Luis worked out 4.2 × 4 = 168. Use an estimate to spot the mistake. What is the right answer? → 16.8Prompt: 4.2 is about 4, so the answer is about 16.
- 1.3 × 9 = ? → 11.7Prompt: Work out 13 × 9 first.
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 with different numbers of places.
- 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
- Move on to: Divide a decimal by a whole number; Decimal multiplication and division problems.
- 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