Mission 7 · Unit 3

Percent Reasoning

6.RP.A.3.C · Unit 3
Today's objective: Find a percent of a quantity and solve percent problems.
Need a hint?
Re-read the problem and underline the numbers and the question. Pick one representation (model, table, or equation), show your steps, and check that your answer makes sense for the situation.

The sixth-grade student council is planning a school supplies drive. They surveyed 250 students about which supplies they need most. The results show that 35% need notebooks, 22% need pencils, 18% need folders, 15% need erasers, and 10% need glue sticks. Your team must convert every percentage to a fraction and a decimal, calculate the exact number of students in each category, verify the total, and recommend how to split a $500 donation budget across the five supply categories proportionally.

School Supplies Survey 250 students surveyed 35% 22% 18% 15% 10% Notebooks Pencils Folders Erasers Glue Sticks

Team Roles

Facilitator Reads the survey scenario aloud, ensures every team member converts at least one percent before the group compares results, and monitors the timer.
Model Builder Creates the fraction-decimal-percent conversion table, draws a bar model or circle graph to represent the survey data, and labels all three forms.
Precision Checker Verifies that all five percentages add to 100%, confirms each student count is a whole number, and checks the budget splits sum to exactly $500.
Reporter Prepares the defense: states the budget recommendation, shows conversion evidence, and explains one rounding decision the team made.

Investigation

The Problem

A survey of 250 sixth graders found that students need five types of school supplies. The results are expressed as percents:

  • Notebooks: 35%
  • Pencils: 22%
  • Folders: 18%
  • Erasers: 15%
  • Glue Sticks: 10%

Your tasks:

  1. Convert each percent to a fraction (simplify!) and a decimal.
  2. Calculate the exact number of students for each category.
  3. Verify that the five student counts add up to 250.
  4. Split a $500 donation budget proportionally based on the survey percentages.
  5. Create a visual model (bar model, pie chart, or number line) that shows how the five categories compare.
Fraction 7/20 Decimal 0.35 Percent 35% divide numerator / denominator x 100 / 100 Example: 35% of 250 students 87.5 students 0.35 x 250 = 87.5 ... but we need a whole number. What happened?

Step-by-Step Investigation Guide

  1. Verify the percents add to 100% Before converting anything, add: 35 + 22 + 18 + 15 + 10. If the sum is not 100%, something is wrong with the data.

    Why must survey percents always add to exactly 100%?

  2. Convert each percent to a fraction Write the percent over 100, then simplify. Example: 35% = 35/100 = 7/20. Find the GCF of the numerator and 100 to simplify.

    Which of the five percents produces the simplest fraction? Which is hardest to simplify?

  3. Convert each fraction to a decimal Divide the numerator by the denominator. Example: 7 / 20 = 0.35. Check: does the decimal make sense compared to the percent?

    How can you check your decimal without a calculator? (Hint: think about equivalent fractions with denominator 10 or 100.)

  4. Calculate the number of students per category Multiply each decimal by 250. Example: 0.35 x 250 = 87.5. Wait -- can you have half a student? Discuss how to handle non-whole results.

    If 0.35 x 250 = 87.5, does the survey data make perfect sense for exactly 250 students? What does this tell you about rounding in surveys?

  5. Calculate the budget allocation Apply each percent to $500. Example: 35% of $500 = 0.35 x 500 = $175. Check that all five amounts add to exactly $500.

    Why is it important that the budget allocations add to exactly $500? What happens if they do not?

  6. Build a visual model and prepare your defense Create a bar model, pie chart, or stacked number line that shows all five categories with fraction, decimal, AND percent labels. Write a one-sentence recommendation for how to spend the $500.

    Which visual model makes it easiest for another student to compare the five categories at a glance?

Percent Calculator Tool

Enter a percent and a total to find the part. Use this to check your work.

% of = 87.5
7/20
0.35

Visual Bar Model

Notebooks
35%
Pencils
22%
Folders
18%
Erasers
15%
Glue
10%

Language Support

Key Vocabulary

Percent: A number out of 100 (per = for each, cent = hundred)
Fraction: A part of a whole written as numerator over denominator
Decimal: A number written with a dot to show parts less than one
Convert: Change from one form to another (same value, different look)
Proportional: Keeping the same ratio when numbers change size
Survey: Asking many people a question and recording answers
Budget: A plan for how to spend a set amount of money
Simplify: Reduce a fraction to its smallest form (divide top and bottom by GCF)

Sentence Frames

  • "___% means ___ out of every 100, which equals the fraction ___."
  • "To convert ___% to a decimal, I divide by 100 and get ___."
  • "___% of 250 students is ___ students because ___ x 250 = ___."
  • "The budget for ___ should be $___ because it is ___% of $500."

Multiple Representations

Conversion Table

Organize all five items in rows with columns for percent, fraction, decimal, students, and budget.

Bar / Strip Model

One long bar = 100%. Divide it into sections proportional to each category.

Pie / Circle Graph

Divide a circle into five sectors. Label each with all three forms.

Double Number Line

Top line shows percents 0-100. Bottom line shows student counts 0-250.