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Math lesson plan Β· 1st grade (Year 2 in England) Β· 60 minutes

Fact families within 20

Addition and subtraction

CCSS 1.OA.B.4CCSS 1.OA.C.6England: Y1 Addition and subtractionEngland: Y2 Addition and subtraction

Objective and success criteria

Students will: Fact families within 20.

  • 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: Subtract by thinking of an addition

Leads to: the next skill in this area.

Materials: Base-ten blocks, Number lines, Hundred square, Mini whiteboards and pens, Printed student sheet (below).

Warm-up Β· 6 min

  • Quick retrieval from earlier learning (Subtract by thinking of an addition). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. 7 + 2 = 9. Use this to find 9 βˆ’ 7. β†’ 2Prompt: 7 and what make 9?
  2. To work out 18 βˆ’ 9, think: 9 + __ = 18 β†’ 9Prompt: Count up from 9 to 18.
  3. Which addition helps you work out 11 βˆ’ 4? (11 + 4 = 15 / 4 + 4 = 8 / 4 + 7 = 11 / 7 + 11 = 18) β†’ 4 + 7 = 11Prompt: The helpful addition uses the same three numbers.

Hook Β· 6 min

  • Give a real shopping total or a score difference and ask for a quick estimate first.
  • Share the objective: Fact families within 20. Read the success criteria together.

I do: model it Β· 12 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: 4 + 3 = 7 is in a fact family. Complete another fact: 3 + 4 = __
  • Step 1: 3 + 4 = 7
  • Answer: 7
  • Pause after each step and ask a student to say what comes next.

We do: guided practice Β· 12 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. 6 + 7 = 13 is in a fact family. Complete another fact: 7 + 6 = __ β†’ 13Prompt: The family uses the numbers 6, 7 and 13.
  2. Which fact belongs to the same family as 3 + 6 = 9? (4 + 6 = 10 / 9 βˆ’ 3 = 6 / 9 + 3 = 12 / 9 βˆ’ 3 = 7) β†’ 9 βˆ’ 3 = 6Prompt: A family only uses 3, 6 and 9.

You do: independent practice Β· 17 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 Β· 7 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. 3 + 4 = 7 is in a fact family. Complete another fact: 7 βˆ’ 4 = __ β†’ 3Prompt: The family uses the numbers 3, 4 and 7.
  2. Which fact belongs to the same family as 4 + 6 = 10? (5 + 6 = 11 / 10 βˆ’ 4 = 7 / 10 + 4 = 14 / 10 βˆ’ 4 = 6) β†’ 10 βˆ’ 4 = 6Prompt: A family only uses 4, 6 and 10.

Watch out for

  • Subtracting the smaller digit from the bigger one in every column (52 βˆ’ 17 = 45).
  • Forgetting to add the regrouped (carried) ten.

Support and stretch

Support

  • Review first: Subtract by thinking of an addition.
  • Use concrete materials: base-ten blocks.
  • 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-1.

Free lesson plan from eurekami.com/lesson-plan-builder

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Fact families within 20

Name

Date

Score/ 8

  1. Question 1

    A fact family uses 7, 6 and one more number. Two facts are 7 + 6 = ? and ? βˆ’ 6 = 7. What is the missing number?

    Answer

  2. Question 2

    10 + 8 = 18 is in a fact family. Complete another fact: 18 βˆ’ 8 = __

    Answer

  3. Question 3

    Which fact belongs to the same family as 10 + 7 = 17?

    • A. 17 βˆ’ 10 = 8
    • B. 11 + 7 = 18
    • C. 17 βˆ’ 10 = 7
    • D. 17 + 10 = 27
  4. Question 4

    A fact family uses 5, 3 and one more number. Two facts are 5 + 3 = ? and ? βˆ’ 3 = 5. What is the missing number?

    Answer

  5. Question 5

    2 + 9 = 11 is in a fact family. Complete another fact: 11 βˆ’ 2 = __

    Answer

  6. Question 6

    Which fact belongs to the same family as 3 + 5 = 8?

    • A. 8 βˆ’ 3 = 5
    • B. 4 + 5 = 9
    • C. 8 βˆ’ 3 = 6
    • D. 8 + 3 = 11
  7. Question 7

    A fact family uses 4, 3 and one more number. Two facts are 4 + 3 = ? and ? βˆ’ 3 = 4. What is the missing number?

    Answer

  8. Question 8

    5 + 4 = 9 is in a fact family. Complete another fact: 9 βˆ’ 4 = __

    Answer

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Answer key: Fact families within 20

  1. 1. 13

  2. 2. 10

  3. 3. C. 17 βˆ’ 10 = 7

  4. 4. 8

  5. 5. 9

  6. 6. A. 8 βˆ’ 3 = 5

  7. 7. 7

  8. 8. 5