CH02-03 lesson

Percent Increase and Decrease Learning Activity

A focused Grade 7 learning session for Percent Increase and Decrease using visual models, worked examples, strategy guidance, and a short mastery check.

15
minutes
6
lesson parts
11
practice items
Learning goal

Students will build Grade 7 mastery of percent increase and decrease using models, equations, and test-style reasoning.

Student goal: I can solve problems involving percent increase and decrease.

concept

Learn the Idea

Percent Increase and Decrease is part of Grade 7 Percents and Financial Literacy. This activity focuses on the central idea students need before they move into independent practice.

Students will build Grade 7 mastery of percent increase and decrease using models, equations, and test-style reasoning.

visual model

See the Math

What to noticeHow to use it
Numbers, units, labels, diagrams, or graphsIdentify what each part represents before calculating.
The relationship in the problemConnect the model to an equation, comparison, or explanation.

Use the figures and worked questions in the practice set below as the visual model for this skill.

worked example

Follow a Worked Example

Read the first practice question slowly. Decide what the question is asking, choose a strategy, solve, and then compare your reasoning with the answer explanation.

For Percent Increase and Decrease, a strong worked example should show the setup, the calculation or model, and a final answer that matches the context.

real world

Connect It to a Real Situation

Many Grade 7 test questions use real situations. Look for quantities, units, rates, measures, expressions, or data values that connect the math to the story.

After solving, explain what the answer means in the situation, not just the number you calculated.

strategy

Avoid Mistakes and Choose a Strategy

  • Underline the exact question before solving.
  • Label units, variables, or graph axes when they appear.
  • Estimate first so unreasonable answers are easier to catch.
  • Review missed questions and write the reason for each mistake.
summary

Remember the Key Idea

I can solve problems involving percent increase and decrease.

Use the warmup, guided question, practice set, and exit questions below to check whether this skill is ready or needs more practice.

Guided to independent practice

Solve before opening the answer

Use scratch paper. The explanation matters more than simply seeing whether the choice is correct.

warmup

2 questions
G7-C02-T03-Q001 About 1 min

A pair of jeans originally costs \($50\). The store raises the price to \($60\). What is the percent increase?

  1. A \(10\%\)
  2. B \(16.7\%\)
  3. C \(20\%\)
  4. D \(30\%\)
Check answer and explanation

Answer C: \(20\%\)

Percent increase \(=\frac{\text{change}}{\text{original}}\times100\%=\frac{60-50}{50}\times100\%=20\%\).

G7-C02-T03-Q002 About 1 min

A tablet costs \($400\) and is discounted by \(25\%\). What is the new price?

  1. A \($100\)
  2. B \($375\)
  3. C \($325\)
  4. D \($300\)
Check answer and explanation

Answer D: \($300\)

Discount amount \(= 25\% \times $400 = 0.25 \times $400 = $100\). New price \(= $400 - $100 = $300\).

guided

1 question
G7-C02-T03-Q003 About 1 min

A restaurant bill was originally \($80\), and after a \(15\%\) increase, what is the new bill?

  1. A \($95\)
  2. B \($12\)
  3. C \($88\)
  4. D \($92\)
Check answer and explanation

Answer D: \($92\)

Increase \(= 15\% \times $80 = 0.15 \times $80 = $12\). New bill \(= $80 + $12 = $92\).

practice

5 questions
G7-C02-T03-Q004 About 1 min

The value of a car decreased from \($24\,000\) to \($18\,000\). What is the percent decrease?

  1. A \(33\%\)
  2. B \(20\%\)
  3. C \(16.7\%\)
  4. D \(25\%\)
Check answer and explanation

Answer D: \(25\%\)

Percent decrease \(= \frac{24000-18000}{24000}\times100\% = \frac{6000}{24000}\times100\% = 25\%\).

G7-C02-T03-Q005 About 1 min

A student's test score improved from \(72\) to \(90\). What is the percent increase in the score?

  1. A \(18\%\)
  2. B \(20\%\)
  3. C \(25\%\)
  4. D \(80\%\)
Check answer and explanation

Answer C: \(25\%\)

Percent increase \(= \frac{90-72}{72}\times100\% = \frac{18}{72}\times100\% = 25\%\).

G7-C02-T03-Q006 About 1 min

A store advertises "Save 30% on all winter coats!" If a coat originally costs \($120\), what is the sale price?

  1. A \($36\)
  2. B \($150\)
  3. C \($90\)
  4. D \($84\)
Check answer and explanation

Answer D: \($84\)

Savings \(= 30\% \times $120 = $36\). Sale price \(= $120 - $36 = $84\).

G7-C02-T03-Q007 About 1 min

The population of a town was \(5\,000\) and increased to \(6\,500\). What is the percent increase?

  1. A \(15\%\)
  2. B \(25\%\)
  3. C \(30\%\)
  4. D \(35\%\)
Check answer and explanation

Answer C: \(30\%\)

Percent increase \(= \frac{6500-5000}{5000}\times100\% = \frac{1500}{5000}\times100\% = 30\%\).

G7-C02-T03-Q008 About 1 min

An item originally marked at \($80\) is reduced to \($60\). What is the percent decrease?

  1. A \(20\%\)
  2. B \(33\%\)
  3. C \(30\%\)
  4. D \(25\%\)
Check answer and explanation

Answer D: \(25\%\)

Percent decrease \(= \frac{80-60}{80}\times100\% = \frac{20}{80}\times100\% = 25\%\).

exit

3 questions
G7-C02-T03-Q009 About 1 min

A basketball player's scoring average was \(18\) points per game. After training, it increased to \(27\) points per game. What is the percent increase?

  1. A \(33.3\%\)
  2. B \(9\%\)
  3. C \(66.7\%\)
  4. D \(50\%\)
Check answer and explanation

Answer D: \(50\%\)

Percent increase \(= \frac{27-18}{18}\times100\% = \frac{9}{18}\times100\% = 50\%\).

G7-C02-T03-Q010 About 1 min

A book costs \($15\). After a \(40\%\) price increase, what is the new cost?

  1. A \($6\)
  2. B \($9\)
  3. C \($21\)
  4. D \($25\)
Check answer and explanation

Answer C: \($21\)

Increase \(= 40\% \times $15 = 0.40 \times $15 = $6\). New cost \(= $15 + $6 = $21\).

G7-C02-T03-Q011 About 1 min

A membership fee was \($200\) per year. This year it was raised by \(12\%\). How much is the new fee?

  1. A \($212\)
  2. B \($220\)
  3. C \($224\)
  4. D \($232\)
Check answer and explanation

Answer C: \($224\)

Increase \(= 12\% \times $200 = 0.12 \times $200 = $24\). New fee \(= $200 + $24 = $224\).

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