Unit 6 · Standard 6.EE.4
Equivalent Expressions
Key Vocabulary Level 1 support
Picture first, then the word, then a plain-language meaning. Say each word out loud.
2x + 4 and 2(x + 2): when x = 3, both = 10; when x = 7, both = 18 — always the same
Equivalent
Expressions that always have the same value.
3x + 2x + 5 simplifies to 5x + 5 — fewer terms, same value
Simplify
To write an expression in a shorter, simpler way.
3x and 7x are like terms (both x); 3x and 3y are NOT (x vs y); 3x and 3x² are NOT (x vs x²)
Like Terms
Terms with the same letter, like 2x and 5x.
4n + 3n = 7n — add the coefficients (4 + 3 = 7) and keep the variable (n)
Combine
To add or subtract terms with the same letter.
In 5x + 3, the coefficient of x is 5 — when x = 2, the 5x part equals 10
Coefficient
The number in front of a letter, like the 3 in 3x.
Key Ideas & Notes
- At the music studio, two producers wrote formulas for the cost of renting equipment.
- Producer A wrote 3x + 2x + 10, and Producer B wrote 5x + 10.
- They look different, but are they really?
- Let's check: if x = 4, Producer A gets 3(4) + 2(4) + 10 = 30, and Producer B gets 5(4) + 10 = 30.
- Sort each expression into the group with its equivalent expression.
Think About It
- Why did both formulas give the same answer?
- What did Producer B do differently from Producer A?
- Would they still match if x = 10?
My Notes
Guided Examples
Example 1
Which expression is equivalent to 4x + 3x?
Solution: 4x + 3x = 7x. Combine the coefficients: 4 + 3 = 7.
Answer: A. 7x
Example 2
Which expression is equivalent to 2(m + 5)?
Solution: 2(m + 5) = 2m + 10 using the distributive property.
Answer: A. 2m + 10
Example 3
Which property is shown: 3(x + 7) = 3x + 21?
Solution: Multiplying 3 by each term inside the parentheses is the distributive property.
Answer: A. Distributive
Write About the Math The Writing Revolution
I can explain my work using the words equivalent, simplify, like terms, and combine.
1. Kernel Sentence subject + verb
Model: Equivalent is expressions that always have the same value.Equivalente es expresiones que siempre tienen el mismo valor.
Write a kernel sentence about equivalent. Use a subject and a verb.Escribe una oración base sobre equivalente. Usa un sujeto y un verbo.
2. Sentence Expansion because · but · so
Kernel: Equivalent matters in mathEquivalente importa en matemáticas
Expand the kernel three ways. Add a reason, a contrast, and a result.
Equivalent matters in math because ___.Equivalente importa en matemáticas porque ___.
Equivalent matters in math, but ___.Equivalente importa en matemáticas, pero ___.
Equivalent matters in math, so ___.Equivalente importa en matemáticas, entonces ___.
3. Sentence Types 4 ways to write a math idea
Tell one true fact about equivalent.Di un hecho verdadero sobre equivalent.
Equivalent ___.
Ask a question about equivalent.Haz una pregunta sobre equivalent.
How does ___ ?¿Cómo ___ ?
Show excitement about equivalent.Muestra entusiasmo sobre equivalent.
Wow, ___ !¡Guau, ___ !
Tell a partner what to do with equivalent.Dile a un compañero qué hacer con equivalent.
First, ___ .Primero, ___ .
4. Explain Your Reasoning use a sentence starter
These expressions are equal because ___.Estas expresiones son iguales porque ___.
I checked by ___.Lo comprobé al ___.
Rewriting helps when ___.Reescribir ayuda cuando ___.
Try It
Solve on your own. Check the answer key when you are done.
1. Which property is shown: 3(x + 7) = 3x + 21?
- Distributive
- Commutative
- Associative
- Identity
2. Simplify: 5n + 2n
- 7n
- 10n
- 7n²
- 52n
Stretch Your Thinking Level 2 enrichment
Challenge task — explain your reasoning in full sentences.
A student says 2x + 3 and 5x are equivalent because both equal 5 when x = 1. Is the student correct? Explain why testing one value is not enough to prove equivalence, and find a value of x where they give different results.
Sentence starter: The student is ___ because ___. When x = 1: 2(1) + 3 = ___ and 5(1) = ___. But when x = ___: 2(___) + 3 = ___ and 5(___) = ___. To prove equivalence, expressions must be equal for ___ values of x.
Reflect — Exit Ticket
Which expression is equivalent to 6n + 4 + 3n − 1?
- 9n + 3
- 9n + 5
- 63n
- 18n + 4
Answer Key & Teacher Guide
- Try It 1: A. Distributive — Multiplying 3 by each term inside the parentheses is the distributive property.
- Try It 2: A. 7n — 5n + 2n = 7n. Add the coefficients: 5 + 2 = 7. The variable stays as n.
- Exit Ticket: A. 9n + 3 — 6n + 3n = 9n and 4 − 1 = 3, so the simplified expression is 9n + 3.
Writing (TWR) — what to look for
- Kernel sentence: A complete sentence needs a subject and a verb. Example: Equivalent is expressions that always have the same value.
- Expansion: because gives a reason, but shows a contrast or exception, so shows a result. Answers vary; each must keep the kernel idea and add the correct kind of detail.
- Sentence types: Statement ends with a period, question with "?", exclamation with "!", and a command starts with an action verb (a "bossy" verb).