Multiply by Tens

Aligned to 3.NBT.A.3 — Common Core State Standards for Mathematics.

What this lesson teaches

To multiply a number by a multiple of 10, first multiply the easy fact, then add one zero to the end.

Example 1

Find 6 × 40. First think 6 × 4 = 24. Then add a zero: 6 × 40 = 240.

Example 2

Find 7 × 80. Think 7 × 8 = 56, then add a zero: 560.

Example 3

This works because 80 is 8 tens. 7 × 8 tens is 56 tens, and 56 tens is 560.

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

Para multiplicar un número por un múltiplo de 10, primero multiplica el hecho fácil y luego agrega un cero al final.

Ejemplo 1: Halla 6 × 40. Primero piensa 6 × 4 = 24. Luego agrega un cero: 6 × 40 = 240.

Ejemplo 2: Halla 7 × 80. Piensa 7 × 8 = 56 y luego agrega un cero: 560.

Ejemplo 3: Esto funciona porque 80 son 8 decenas. 7 × 8 decenas son 56 decenas, y 56 decenas son 560.

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