Family Math Studio Grade 6 Math · Neft Teacher

Family Math Studio · Lesson guide Guía de la lección

Unit 6, Lesson 12: Least Common Multiple

Standard 6.NOS.4

What students are learning Qué aprenden

Key idea: The least common multiple (LCM) is the smallest number that two numbers both count up to. Count by 4s: 4, 8, 12. Count by 6s: 6, 12. The first number on both lists is 12, so the LCM of 4 and 6 is 12.Idea clave: El mínimo común múltiplo (m.c.m.) es el número más pequeño al que llegan contando dos números. Cuenta de 4 en 4: 4, 8, 12. Cuenta de 6 en 6: 6, 12. El primer número en las dos listas es 12, así que el m.c.m. de 4 y 6 es 12.

Words to know Palabras clave

Least Common Multiple Mínimo común múltiplo
The smallest number both numbers count up to.
El número más pequeño al que llegan ambos al contar.
Multiple Múltiplo
A number you land on when you count by it.
Un número al que llegas al contar de a saltos con otro.
Common multiple Múltiplo común
A number you reach when counting by each number.
Un número al que llegas contando de a saltos con cada número.
Skip counting Conteo salteado
Counting by a number, like 2, 4, 6.
Contar de un número en un número, como 2, 4, 6.
Prime factorization Factorización prima
A number written as a product of primes.
Un número escrito como producto de números primos.

Sentence starters Frases para empezar

I know ___ because ___.

First, I ___. Then, I ___.

The answer is ___, so ___.

How we did it in class today Cómo lo hicimos hoy en clase

  1. I want the LCM of 4 and 6. I skip count the multiples of 4: 4, 8, 12, 16, 20, 24.
  2. Then I skip count the multiples of 6: 6, 12, 18, 24.
  3. I look for the first number in BOTH lists. 12 is in both lists, and it comes before 24.
  4. So the LCM of 4 and 6 is 12. I check: 12 ÷ 4 = 3 and 12 ÷ 6 = 2, so both go into 12 evenly.

Play with today's math Jueguen con las matemáticas

Interactive Lesson Model — This is the exact same interactive tool your student used in class today. Change the numbers and watch what happens!

Modelo interactivo de la lección — Esta es la misma herramienta interactiva que su estudiante usó en clase hoy. ¡Cambie los números y observe qué sucede!

Works on a phone, a tablet, or a computer. Nothing to install, nothing to sign in to.

Try this together Inténtenlo juntos

Pick one question to talk about. You don't need to do them all!

Match each pair of numbers to their LCM.

LCM(2, 5)

Check the answer

The answer is: 10

Take-home sheet Hoja para llevar a casa

Lesson 6.12: Print the sheet (PDF) · Answers and talk notes (PDF) · Edit it (Word)

Lección 6.12: Imprimir la hoja (PDF) · Respuestas y notas para conversar (PDF) · Editarla (Word)

If they get stuck... Si se traban...

Watch out for this: A common mistake in Least Common Multiple is multiplying the two numbers together instead of listing multiples to find the smallest shared one. For example, for 4 and 6, a student calculates 4 × 6 = 24 and calls that the LCM, but the actual least common multiple is 12 (multiples of 4: 4, 8, 12; multiples of 6: 6, 12 — 12 is the first number that appears in both lists). This shortcut only works when the two numbers share no common factors (like 4 and 9, where the LCM really is 36 = 4 × 9); for numbers like 4 and 6 that share a factor of 2, multiplying overshoots the true LCM. Always list multiples of both numbers and pick the first one that appears in both lists.

Try asking: "Can you show me how you got that? Did we miss a step?"
Pregunte: «¿Puedes mostrarme cómo lo hiciste? ¿Nos saltamos algún paso?» Hablar de las matemáticas en voz alta ayuda mucho.

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