Thinkabara

🧮 1st Grade · Math1.OA.B.4Unit 4: Subtraction strategies within 20

Think addition to subtract

Google Classroom

🎯 Objective: Students solve 13 − 8 by thinking 8 + ? = 13.

Lesson outline

  1. Show a fact family triangle for 8, 5, 13.
  2. Model “subtract by adding up”.
  3. Practice with fact cards and a partner.
  4. Exit: 15 − 9 using addition.

Lesson 1 of 5 in this unit. In the Lesson Planner this lesson takes 1–3 class periods depending on your timetable: day 1 introduce & model, then practice, small-group reteach and a quick check.

📐 Standard

1.OA.B.4

Common Core State Standards for Mathematics, Grade 1 — typical US scope & sequence

🏁 Unit goals

  • Subtract within 20 using think-addition, counting back and making ten
  • Relate subtraction to addition

✅ Check for understanding

End with the exit ticket in the outline. Sort answers into got it / almost / not yet and start the next lesson with a 5-minute reteach for the “not yets”.

Practice & resources on Thinkabara

🎯 Practice: Add & subtract within 20🖨️ Worksheet: Addition Within 20🖨️ Worksheet: Subtraction Within 20📚 All 1st Grade skills🎮 Learning games⚡ Capy Live class quiz

🗓️ Plan the whole year like this

Add 1st Grade Math to your free Lesson Planner: enter your timetable once and every period shows the next lesson, skipping weekends and school breaks.

Add to my planner See the year’s sequence

More lessons in “Subtraction strategies within 20”

  1. Think addition to subtract
  2. Subtract by making ten
  3. Subtraction on a number line
  4. Subtraction story problems
  5. Subtraction facts fluency

Something to improve in this lesson? Tell us.