Math lesson plan · 5th grade (Year 6 in England) · 45 minutes
Round decimals
Decimals and percentages
CCSS 5.NBT.A.4England: Y5 Fractions (including decimals)England: Y6 Fractions (including decimals)
Objective and success criteria
Students will: Round 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: Decimals to thousandths; Round to the nearest 10 or 100
Leads to: Error intervals and bounds
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 (Decimals to thousandths; Round to the nearest 10 or 100). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Write 513/1000 as a decimal. → 0.513Prompt: Thousandths need three decimal places.
- Write as one decimal: 3 + 0.04 + 0.002 → 3.042Prompt: Each part gives the digit in one place.
- Write 678/1000 as a decimal. → 0.678Prompt: Thousandths need three decimal places.
Hook · 5 min
- Show two prices or race times with decimals and ask which is bigger, then why.
- Share the objective: Round 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: Round 17.2 to 1 decimal place.
- Step 1: The next digit is 0.
- Step 2: 17.2
- Answer: 17.2
- 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.
- Round 34.718 to the nearest whole number. → 35Prompt: Find the digit in the place you are rounding to.
- Aisha's lunch costs $5.21. Round the cost to the nearest whole dollar. (Type the number only.) → 5Prompt: Look at the digit after the decimal point.
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.
- Fatima's lunch costs $5.55. Round the cost to the nearest whole dollar. (Type the number only.) → 6Prompt: Look at the digit after the decimal point.
- Round 3.27 to 2 decimal places. → 3.27Prompt: Find the digit in the place you are rounding to.
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: Decimals to thousandths.
- 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: Error intervals and bounds.
- 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