Write and Evaluate Algebraic Expressions
Name Period
Objectives / Objetivos
Content Objective: I can write an algebraic expression for a real situation and evaluate it for a given value of the variable.
Language Objective: I can explain my expression using the words variable, term, coefficient, constant, substitute, and evaluate.
Key Idea / Idea clave
Writing & Evaluating Algebraic Expressions. 1. Define the variable to represent the unknown quantity. 2. Translate mathematical phrases into operations, coefficients, and constants. 3. Evaluate by substituting given numerical values for the variable
I Notice / Observo
- What value changes depending on how many people come?
- What stays the same no matter the number of tickets?
I Wonder / Me pregunto
- What if there were two different ticket prices — regular and VIP?
Vocabulary / Vocabulario
| Term / Término | Definition / Definición |
|---|---|
| Write Algebraic Expressions Escribir expresiones algebraicas | Translate words or a situation into numbers, variables, and operation symbols. Traducir palabras o una situación a números, variables y símbolos de operaciones. |
| Variable Variable | A letter that stands for a number that is unknown or can change. Una letra que representa un número desconocido o que puede cambiar. |
| Algebraic Expression Expresión algebraica | A math phrase that has at least one letter. Una frase matemática que tiene al menos una letra. |
| Coefficient Coeficiente | The number in front of a letter, like the 3 in 3x. El número frente a una letra, como el 3 en 3x. |
| Constant Constante | A fixed number in an expression or equation that does not change. Un número fijo en una expresión o ecuación que no cambia. |
| Like terms Términos semejantes | Terms with the same letter raised to the same power, like 2x and 5x. Términos con la misma letra elevada a la misma potencia, como 2x y 5x. |
Practice Preview / Vista previa de práctica
Read each task. Show your work in the spaces provided and explain how you know.
1. Which expression represents 'the product of 6 and a number n'?
- A 6n
- B 6 + n
- C n − 6
- D n ÷ 6
Answer:
2. Match each word phrase to its algebraic expression. Write a letter for each phrase, then explain one match.
Write the letter of the matching item in the blank.
| 1. | twice a number k | A. | 2k | |
| 2. | a number b divided by 5 | B. | 3c + 4 | |
| 3. | the sum of a number d and 15 | C. | d + 15 | |
| 4. | 10 decreased by a number r | D. | h ÷ 2 | |
| 5. | 4 more than triple a number c | E. | 10 − r | |
| 6. | half of a number h | F. | b ÷ 5 |
3. Match each word phrase to its algebraic expression.
Write the letter of the matching item in the blank.
| 1. | the product of 5 and n | A. | z + 7 | |
| 2. | 8 less than a number w | B. | p + 12 | |
| 3. | a number p increased by 12 | C. | y ÷ 4 | |
| 4. | twice a number x, plus 3 | D. | 5n | |
| 5. | a number y divided by 4 | E. | w − 8 | |
| 6. | 7 more than a number z | F. | 2x + 3 |
4. Find the Translation Error
Which step has the mistake, and what should it be?
Reflection / Reflexión
One thing I learned today / Una cosa que aprendí hoy: