Solve Problems with Unit Rates

6.AT.2 · Unit 4 · Lesson 7

Name   Period

Objectives / Objetivos

Content Objective: I can solve real-world problems by using unit rates to compare options.

Language Objective: I can explain my comparison using the words unit rate, better buy, per unit, and rate.

Key Idea / Idea clave

Divide the price by the number of items to get the cost per unit. The lower cost per unit is the better buy.

I Notice / Observo

  • How can you compare deals when the quantities are different?
  • What operation helps you find the cost for just one item?

I Wonder / Me pregunto

  • Does the biggest package always give the best unit rate?

Vocabulary / Vocabulario

Term / TérminoDefinition / Definición
Unit Rate
Tasa unitaria		A rate for just 1 of something, like cost for 1 item.
Una tasa para solo 1 de algo, como el precio de 1 artículo.
Better Buy
Mejor compra		The choice that costs less for each item.
La opción que cuesta menos por cada artículo.
Comparison
Comparación		Looking at two or more amounts to see how they are related.
Mirar dos o más cantidades para ver cómo se relacionan.
Per Unit
Por unidad		For each single item.
Por cada artículo.
Rate
Tasa		A ratio comparing two amounts with different units, like miles per hour.
Una razón que compara dos cantidades con unidades distintas, como millas por hora.
Proportion
Proporción		A math sentence saying two ratios are equal. It helps find a missing number.
Una oración matemática que dice que dos razones son iguales. Ayuda a hallar un número que falta.

Practice Preview / Vista previa de práctica

  1. Which is the better buy: 6 bouncy balls for $4.50 or 10 bouncy balls for $8.00?
    1. 6 for $4.50 — $0.75 each
    2. 10 for $8.00 — $0.80 each
    3. They cost the same per ball
    4. Not enough information
  2. Find the unit rate for each deal and identify the better buy.
  3. A machine dispenses 24 tokens in 3 minutes. At this rate, how many tokens does it dispense in 10 minutes?
    1. 80 tokens
    2. 60 tokens
    3. 72 tokens
    4. 240 tokens
  4. Find the Unit Rate Error
    1. Step 1: Which is the better buy: 5 lb for $8.75 or 3 lb for $5.10? — Compare two deals
    2. Step 2: Find unit rate for Deal 1 — 5 ÷ $8.75 = 0.57 lb per dollar
    3. Step 3: Find unit rate for Deal 2 — 3 ÷ $5.10 = 0.59 lb per dollar
    4. Step 4: Compare — 0.59 > 0.57, so Deal 2 is the better buy

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

Reflection / Reflexión

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