Subtracting Tens

Aligned to 1.NBT.C.6 — Common Core State Standards for Mathematics.

What this lesson teaches

When we subtract tens from tens, we just count how many tens are left.

Example 1

50 - 20. That is 5 tens take away 2 tens, which leaves 3 tens. So 50 - 20 = 30.

Example 2

80 − 30. That is 8 tens take away 3 tens, leaving 5 tens. So 80 − 30 = 50.

Example 3

90 − 90 = 0. Taking away every ten leaves no tens at all.

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

Cuando restamos decenas de decenas, solo contamos cuántas decenas quedan.

Ejemplo 1: 50 - 20. Eso es 5 decenas menos 2 decenas, y quedan 3 decenas. Así que 50 - 20 = 30.

Ejemplo 2: 80 − 30. Eso es 8 decenas menos 3 decenas, y quedan 5 decenas. Así que 80 − 30 = 50.

Ejemplo 3: 90 − 90 = 0. Quitar todas las decenas no deja ninguna decena.

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