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Hair Today, Gone Tomorrow (Updated!)

How long does it take to donate hair?

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Hair Today, Gone Tomorrow (Updated!)

How long does it take to donate hair?

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Check it out! This lesson was just updated in September 2024, and we hope you love the new and improved version. If you've already prepped an earlier version, fear not, you can still find those here through Thursday December 5, 2024.

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Hair Today Gone Tomorrow - Student Handout.pdf
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Hair Today Gone Tomorrow - Teacher Guide.pdf
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2023-2024 Versions

In the fall of 2024, Citizen Math released updated versions of every lesson in our library, plus a few new ones! We know you may have already prepped an earlier version or planned a repeat of last year, so we're continuing to make these earlier versions available through Thursday December 5, 2024.

You can find the new lessons through the regular search, and we hope you love them as much as we do. You can read more about these updates in Our Community.

Every year, thousands of children lose their hair to leukemia and other medical conditions. Fortunately, there are organizations that help them by turning donated hair into wigs. How long does it take to donate hair? Donating hair is a generous act, but it also takes a long time to grow an entire wig’s worth of hair.

Students write and solve linear equations to determine how long it would take to donate a wig’s worth of hair and discuss ways they can support peers with conditions like Leukemia and alopecia.

REAL WORLD TAKEAWAYS

  • Every year, many children lose their hair due to medical conditions. To help them, certain organizations create wigs from donated hair.
  • It takes approximately 100 inches of hair to make a single wig. It would take an individual person more than 16-20 years to donate a complete wig. If a classroom full of students worked together, they could donate a full wig in a fraction of the time!
  • Groups of people can often make an impact more quickly by working together.

MATH OBJECTIVES

  • Write and solve one-variable equations to solve real-world problems
Appropriate most times as students are developing conceptual understanding.
Grade 7
Equations & Expressions
Grade 7
Equations & Expressions
Content Standards 7.EE.2 Understand that rewriting an expression in different forms in a problem context can shed light on the problem and how the quantities in it are related. For example, a + 0.05a = 1.05a means that "increase by 5%" is the same as "multiply by 1.05." 7.EE.3 Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies. For example: If a woman making $25 an hour gets a 10% raise, she will make an additional 1/10 of her salary an hour, or $2.50, for a new salary of $27.50. If you want to place a towel bar 9 3/4 inches long in the center of a door that is 27 1/2 inches wide, you will need to place the bar about 9 inches from each edge; this estimate can be used as a check on the exact computation. 7.EE.4 Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities. (a) Solve word problems leading to equations of the form px + q = r and p(x + q) = r, where p, q, and r are specific rational numbers. Solve equations of these forms fluently. Compare an algebraic solution to an arithmetic solution, identifying the sequence of the operations used in each approach. For example, the perimeter of a rectangle is 54 cm. Its length is 6 cm. What is its width? (b) Solve word problems leading to inequalities of the form px + q > r or px + q < r, where p, q, and r are specific rational numbers. Graph the solution set of the inequality and interpret it in the context of the problem. For example: As a salesperson, you are paid $50 per week plus $3 per sale. This week you want your pay to be at least $100. Write an inequality for the number of sales you need to make, and describe the solutions.
Mathematical Practices MP.1 Make sense of problems and persevere in solving them. MP.2 Reason abstractly and quantitatively. MP.4 Model with mathematics. MP.7 Look for and make use of structure. MP.8 Look for and express regularity in repeated reasoning.

Other Grade 7 Lessons

Big Foot Conspiracy (Updated!)

Should people with small feet pay less for shoes?

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Great anytime, including at the beginning of a unit before students have any formal introduction to the topic.

Common Cents (Updated!)

Should the United States get rid of the penny?

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Rational Numbers
Appropriate most times as students are developing conceptual understanding.

To Have and to Hold (Updated!)

Is renting a storage unit a good idea?

Grade 7
Equations & Expressions
Appropriate most times as students are developing conceptual understanding.

Axle Roads (Updated!)

How do vehicles turn so smoothly?

Grade 7
Measuring Circles
Appropriate most times as students are developing conceptual understanding.

Grading Scales of Justice (Updated!)

What’s the best grading policy?

Grade 7
Percents & Proportions
Appropriate most times as students are developing conceptual understanding.

Big Foot Conspiracy (Updated!)

Should people with small feet pay less for shoes?

Grade 7
Ratios & Proportions
Great anytime, including at the beginning of a unit before students have any formal introduction to the topic.

Common Cents (Updated!)

Should the United States get rid of the penny?

Grade 7
Rational Numbers
Appropriate most times as students are developing conceptual understanding.

To Have and to Hold (Updated!)

Is renting a storage unit a good idea?

Grade 7
Equations & Expressions
Appropriate most times as students are developing conceptual understanding.

Axle Roads (Updated!)

How do vehicles turn so smoothly?

Grade 7
Measuring Circles
Appropriate most times as students are developing conceptual understanding.

Grading Scales of Justice (Updated!)

What’s the best grading policy?

Grade 7
Percents & Proportions
Appropriate most times as students are developing conceptual understanding.