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Unit 1: Number System Launch Lesson 1-3 6.NOS.4

Least Common Multiple

I can find the least common multiple (LCM) of two numbers by listing or comparing their multiples.

Speaking and writing goal: I can explain how I found the LCM using the words multiple, common multiple, skip counting, and least common multiple.

What Your Child Is Learning

In this lesson, students practice how to find the least common multiple (lcm) of two numbers by listing or comparing their multiples. They learn to show their thinking with numbers, pictures, words, or a model. The goal is not just getting an answer. Students should be able to explain why the answer makes sense.

Why This Matters

This skill supports everyday problem solving with money, measurements, games, planning, and checking whether an answer is reasonable.

What It May Look Like In Class

Your child may use the interactive lesson, guided notes, examples from the board, partner talk, and short practice problems. They may be asked to solve, draw a model, label important numbers, and explain their reasoning in a sentence.

How You Can Help At Home

You do not need to teach a new method. Ask your child to read the problem out loud, circle the important numbers, and explain what they tried first. Helpful questions include: What do you know? What are you trying to find? Does your answer make sense?

Apoyo para familias en español

Qué está aprendiendo su hijo/a

En esta lección, su hijo/a practica usar números con cuidado y explicar sus pasos. Puede usar dibujos, números, palabras o modelos para mostrar su pensamiento. Lo más importante es que pueda explicar por qué su respuesta tiene sentido.

Por qué es importante

Esta habilidad ayuda con dinero, medidas, juegos, planificación y con revisar si una respuesta es razonable.

Cómo puede ayudar en casa

No necesita ser experto/a en matemáticas. Pídale a su hijo/a que lea el problema en voz alta, marque los números importantes y explique su primer paso. Puede preguntar: ¿Qué sabes? ¿Qué necesitas encontrar? ¿Tu respuesta tiene sentido?

Key Vocabulary

Multiple Múltiplo

What you get when you multiply a number by 1, 2, 3, and so on.

Example: 12 is a multiple of 4

Least common multiple Mínimo común múltiplo

The smallest number that two or more numbers both go into.

Common multiple Múltiplo común

A number that two or more numbers both go into.

Skip counting Conteo salteado

Counting by a number, like 2, 4, 6, to list its multiples.

Prime factorization Factorización prima

Writing a number as prime numbers multiplied together. It helps you find the LCM.

Try It Together

Pick one or two problems. Let your child explain the first step before opening the answer.

  1. Estimate first, then solve: 48 / 6.
    Show answer

    Estimate about 50 / 5 = 10; exact answer 8

  2. Explain one way to check an answer.
    Show answer

    Use the opposite operation, a model, or estimation.

  3. Write a number story for 12 x 3.
    Show answer

    Answers vary; for example, 12 rows of 3 chairs.

  4. What should you do if an answer seems too big or too small?
    Show answer

    Re-read the problem and check with an estimate.