Adding Three Numbers

Aligned to 1.OA.A.2 — Common Core State Standards for Mathematics.

What this lesson teaches

To add three numbers, we add two of them first, then add the last one to that answer.

Example 1

2 + 3 + 4. First add 2 + 3 = 5. Then add 5 + 4 = 9.

Example 2

6 + 4 + 7. Add 6 + 4 = 10 first because it makes a ten, then 10 + 7 = 17.

Example 3

5 + 8 + 5. You may start anywhere, so pair the two 5s: 5 + 5 = 10, then 10 + 8 = 18.

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

Para sumar tres números, sumamos dos de ellos primero y luego le sumamos el último a esa respuesta.

Ejemplo 1: 2 + 3 + 4. Primero suma 2 + 3 = 5. Luego suma 5 + 4 = 9.

Ejemplo 2: 6 + 4 + 7. Suma primero 6 + 4 = 10 porque forma una decena, y luego 10 + 7 = 17.

Ejemplo 3: 5 + 8 + 5. Puedes empezar por donde quieras, así que junta los dos 5: 5 + 5 = 10, y luego 10 + 8 = 18.

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