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Adding Several Two-Digit Numbers

  • Grade 2
  • Mathematics
  • 2.NBT.B.6
  • Number & Operations in Base Ten
  • Free lesson

Aligned to 2.NBT.B.6 — Common Core State Standards for Mathematics.

What this lesson teaches

To add three or four numbers, add the tens together and the ones together, then put the parts back together.

Worked examples

Example 1

12 + 23 + 14: add tens 10+20+10 = 40; add ones 2+3+4 = 9; then 40 + 9 = 49.

Example 2

21 + 13 + 32: tens 20+10+30 = 60; ones 1+3+2 = 6; then 60 + 6 = 66.

Example 3

18 + 12 + 25: the ones are 8+2+5 = 15, which is more than 9, so trade 10 of them for a ten. Tens 10+10+20+10 = 50, plus 5 ones = 55.

Practice questions

  1. Add 21 + 32 + 15.
  2. Add 10 + 20 + 30 + 25.
  3. Add 14 + 14 + 14.

Watch the lesson

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En español

Sumar varios números de dos dígitos

Para sumar tres o cuatro números, suma las decenas juntas y las unidades juntas, y luego une las partes.

Ejemplo 1: 12 + 23 + 14: suma las decenas 10+20+10 = 40; suma las unidades 2+3+4 = 9; luego 40 + 9 = 49.

Ejemplo 2: 21 + 13 + 32: decenas 20+10+30 = 60; unidades 1+3+2 = 6; luego 60 + 6 = 66.

Ejemplo 3: 18 + 12 + 25: las unidades son 8+2+5 = 15, que es más de 9, así que cambia 10 de ellas por una decena. Decenas 10+10+20+10 = 50, más 5 unidades = 55.

More Number & Operations in Base Ten lessons

Adding and Subtracting within 1002.NBT.B.5Hundreds, Tens, and Ones2.NBT.A.1Counting and Skip-Counting2.NBT.A.2Reading and Writing Numbers to 10002.NBT.A.3Comparing Three-Digit Numbers2.NBT.A.4Adding and Subtracting within 10002.NBT.B.7

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