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 + 0.9 + 0.01 + 0.008 → 3.918Prompt: Each part gives the digit in one place.
- Write 447/1000 as a decimal. → 0.447Prompt: 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 74.744 to 2 decimal places. → 74.74Prompt: Find the digit in the place you are rounding to.
- Elena's lunch costs $2.98. Round the cost to the nearest whole dollar. (Type the number only.) → 3Prompt: 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.
- Round 18.072 to 2 decimal places. → 18.07Prompt: Find the digit in the place you are rounding to.
- Noah's lunch costs $3.80. Round the cost to the nearest whole dollar. (Type the number only.) → 4Prompt: Look at the digit after the decimal point.
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