Thinkabara

🧮 1st Grade · Math1.NBT.B.2bUnit 6: Counting & place value to 120

Teen numbers and decade numbers

Google Classroom

🎯 Objective: Students see 11–19 as a ten and some ones and 10, 20, …, 90 as tens.

Lesson outline

  1. Show 16 and 60: what is the difference?
  2. Build both with blocks.
  3. Sort cards: teen numbers vs decade numbers.
  4. Exit: build 19 and 90.

Lesson 4 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.NBT.B.2b

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

🏁 Unit goals

  • Count, read and write numbers to 120
  • Understand two-digit numbers as tens and ones

✅ 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: Place value to 120📚 All 1st Grade skills🎮 Learning games⚡ Capy Live class quiz

🗓️ Plan the whole year like this

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More lessons in “Counting & place value to 120”

  1. Counting to 120
  2. Groups of ten
  3. Tens and ones
  4. Teen numbers and decade numbers
  5. Different ways to make a number

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