Solve One-Step Addition and Subtraction Equations

6.AT.8 · Unit 7 · Lesson 2

Name   Period

Objectives / Objetivos

Content Objective: I can solve one-step addition and subtraction equations using inverse operations.

Language Objective: I can explain my steps using the words equation, inverse operation, isolate, and solution.

Key Idea / Idea clave

Undo the operation with its inverse, and do it to both sides to keep the equation balanced.

I Notice / Observo

  • What operation connects the locker number and 23?
  • What does n represent in the equation?

I Wonder / Me pregunto

  • What if the message said 'the number minus 23 equals 58' instead?

Vocabulary / Vocabulario

Term / TérminoDefinition / Definición
Equation
Ecuación		A math sentence with an equal sign showing both sides are the same.
Una oración matemática con un signo igual que muestra que ambos lados son iguales.
Inverse operation
Operación inversa		Two math actions that undo each other, like × and ÷.
Dos operaciones que se deshacen entre sí, como × y ÷.
Isolate
Despejar		To get the letter by itself on one side.
Dejar la letra sola en un lado.
Solution
Solución		A number that makes the equation or inequality true.
Un número que hace verdadera la ecuación o desigualdad.
One-step equation
Ecuación de un paso		An equation you can solve in a single step using one inverse operation.
Una ecuación que puedes resolver en un solo paso usando una operación inversa.
Balance
Equilibrio		Keeping both sides of an equation equal by doing the same thing to each side.
Mantener ambos lados de una ecuación iguales haciendo lo mismo a cada lado.

Practice Preview / Vista previa de práctica

  1. Solve: x + 9 = 15
    1. x = 6
    2. x = 24
    3. x = 9
    4. x = 15
  2. Solve: m − 14 = 32
  3. Complete the table: identify the inverse operation, solve, and check.
  4. Find the Equation Error
    1. Step 1: Equation — x − 18 = 45
    2. Step 2: Identify inverse — Inverse of subtraction is subtraction
    3. Step 3: Apply to both sides — x − 18 − 18 = 45 − 18
    4. Step 4: Simplify — x = 27

    Which step has the mistake? Explain it and write the correct work.

Reflection / Reflexión

One thing I learned today / Una cosa que aprendí hoy: