Math lesson plan · 1st grade (Year 2 in England) · 45 minutes
Split two-digit numbers into tens and ones
Number sense
CCSS 1.NBT.B.2England: Y1 Number and place valueEngland: Y2 Number and place value
Objective and success criteria
Students will: Split two-digit numbers into tens and ones.
- 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: Tens and ones
Leads to: The same number made in different ways with tens and ones; Spot the place-value mistake
Materials: Place value chart, Base-ten blocks or a number line, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Tens and ones). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- How many tens are in 72? → 7Prompt: In a two-digit number, the left digit tells the tens and the right digit tells the ones.
- What number is 6 tens and 0 ones? → 60Prompt: What is 6 tens worth?
- 64 = 6 tens and how many ones? → 4Prompt: In a two-digit number, the left digit tells the tens and the right digit tells the ones.
Hook · 5 min
- Show a number in the news or a price tag and ask what each digit is worth.
- Share the objective: Split two-digit numbers into tens and ones. 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: 86 = __ + 6
- Step 1: 86 = 80 + 6
- Step 2: 80
- Answer: 80
- 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.
- 12 = __ + 2 → 10Prompt: How many tens and how many ones are in 12?
- 7 + 10 = ? → 17Prompt: One number is the tens and the other is the ones.
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.
- 17 = 10 + __ → 7Prompt: How many tens and how many ones are in 17?
- Which shows 23 split into tens and ones? (20 + 3 / 2 + 3 / 20 + 30 / 30 + 2) → 20 + 3Prompt: 23 has 2 tens. What are 2 tens worth?
Watch out for
- Reading 1,045 as one thousand four hundred five: point to each place and say its value.
- Thinking a longer number is always bigger, even with decimals (0.45 vs 0.5).
Support and stretch
Support
- Review first: Tens and ones.
- Use concrete materials: place value chart.
- 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: The same number made in different ways with tens and ones; Spot the place-value mistake.
- 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-1.
Free lesson plan from eurekami.com/lesson-plan-builder