Unit 4 · Standard 6.RP.3c

Use Percent to Solve Problems

Lesson 4-5

Name:Date:Class:

Key Vocabulary Level 1 support

Picture first, then the word, then a plain-language meaning. Say each word out loud.

20% off $50 → discount is $10

Discount

Money taken off the first price to make it cheaper.

A $30 item with 10% markup sells for $33

Markup

Money added to the cost to set the selling price.

Illustration of Tax: Extra money added to a price for the government.

6% tax on $20 adds $1.20

Tax

Extra money added to a price for the government.

Illustration of Tip: Extra money you give for good service.

15% tip on $40 = $6

Tip

Extra money you give for good service.

50% means 50 out of 100

Percent

A way to compare a number to 100, shown with the % sign.

Key Ideas & Notes

Welcome to the arcade prize shop!
You've been saving up tickets and now it's time to spend them.
Some prizes are on sale with discounts, but the shop also charges a 5% ticket tax on purchases.
Plus, there's a 10% markup on limited-edition prizes.
Complete the table to find the final ticket cost for each arcade prize after discounts and taxes.

Think About It

What happens to the price when there is a discount?
What happens to the price when tax is added?
Does it matter whether you apply the discount or tax first?

My Notes

Guided Examples

Example 1

A prize costs 120 tickets and is 25% off. What is the sale price?

Solution: 25% of 120 = 0.25 × 120 = 30. Sale price: 120 − 30 = 90 tickets.

Answer: A. 90 tickets

Example 2

A meal costs $20. You leave a 15% tip. How much is the tip?

Solution: 15% of $20 = 0.15 × 20 = $3.00.

Answer: A. $3.00

Example 3

A shirt costs $40 and the sales tax is 5%. What is the total cost including tax?

Solution: Tax: 0.05 × $40 = $2.00. Total: $40 + $2 = $42.00.

Answer: A. $42.00

Write About the Math The Writing Revolution

I can explain my solution using the words discount, markup, tax, tip, and percent.

1. Kernel Sentence subject + verb

Model: Percent is a way to compare a number to 100, shown with the % sign.Porcentaje es una manera de comparar un número con 100, con el signo %.

Write a kernel sentence about percent. Use a subject and a verb.Escribe una oración base sobre porcentaje. Usa un sujeto y un verbo.

2. Sentence Expansion because · but · so

Kernel: Percent matters in mathPorcentaje importa en matemáticas

Expand the kernel three ways. Add a reason, a contrast, and a result.

becauseporque

Percent matters in math because ___.Porcentaje importa en matemáticas porque ___.

butpero

Percent matters in math, but ___.Porcentaje importa en matemáticas, pero ___.

soentonces

Percent matters in math, so ___.Porcentaje importa en matemáticas, entonces ___.

3. Sentence Types 4 ways to write a math idea

StatementAfirmación

Tell one true fact about percent.Di un hecho verdadero sobre percent.

Percent ___.

QuestionPregunta

Ask a question about percent.Haz una pregunta sobre percent.

How does ___ ?¿Cómo ___ ?

ExclamationExclamación

Show excitement about percent.Muestra entusiasmo sobre percent.

Wow, ___ !¡Guau, ___ !

CommandMandato

Tell a partner what to do with percent.Dile a un compañero qué hacer con percent.

First, ___ .Primero, ___ .

4. Explain Your Reasoning use a sentence starter

The percent stands for ___.El porcentaje representa ___.

I solved it by ___.Lo resolví al ___.

This is like a ___ in real life.Esto es como un ___ en la vida real.

Try It

Solve on your own. Check the answer key when you are done.

1. A store marks up a $30 item by 40%, then a customer gets 10% off. What is the final price?

$37.80
$39.00
$42.00
$36.00

Show your work:

2. A restaurant bill is $35. You want to leave a 20% tip. What is the total amount you pay?

$42.00
$40.00
$38.50
$55.00

Show your work:

Stretch Your Thinking Level 2 enrichment

Challenge task — explain your reasoning in full sentences.

A store has a 20% off sale, then takes an additional 10% off the sale price. Is this the same as 30% off the original? Use $100 as the original price. Show your work for both scenarios and explain the difference.

Sentence starter: Taking 20% off then 10% off gives a final price of $___, but 30% off the original gives $___. The difference is $___ because ___.

Show your work:

Reflect — Exit Ticket

A jacket costs $80 and is 35% off. Sales tax is 5%. What is the final price?

$54.60
$52.00
$56.00
$49.40

Your answer:

Answer Key & Teacher Guide

Try It 1: A. $37.80 — Markup: $30 × 1.40 = $42. Discount: $42 × 0.10 = $4.20. Final: $42 − $4.20 = $37.80.
Try It 2: A. $42.00 — Tip: 0.20 × $35 = $7.00. Total: $35 + $7 = $42.00.
Exit Ticket: A. $54.60 — Discount: 0.35 × $80 = $28. Sale price: $80 − $28 = $52. Tax: 0.05 × $52 = $2.60. Final: $52 + $2.60 = $54.60.

Writing (TWR) — what to look for

Kernel sentence: A complete sentence needs a subject and a verb. Example: Percent is a way to compare a number to 100, shown with the % sign.
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).