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Lesson plan Grade 7 Math

Ravensden's Operator Pay Ladder: A Grade 7 Percent Lesson

A 45-minute grade 7 math lesson where students work out percent raises across a fictional water district's operator certification levels and yearly pay.

Objectives

  1. Students will calculate the percent increase between two hourly wages on a certification ladder.
  2. Students will apply a stated percent raise to find the next wage on the ladder.
  3. Students will convert hourly pay to yearly pay and compare it with a published national median.

Vocabulary

Key words: certification, hourly wage, percent increase, median, licensure

Teacher overview

Water and wastewater treatment plant and system operators hold state licenses, and most utilities pay by certification level, so an operator's wage rises as each new exam is passed. Nationally, operators earned a median $60,020 per year in May 2025 according to the Bureau of Labor Statistics, and the work is usually entered with a high school diploma, on-the-job training, and a state operator license, though many operators also arrive through certificate programs or two-year and four-year degrees. This lesson uses a fictional four-step pay ladder at the Ravensden Water District to practice percent increase. The error to watch for is dividing the raise by the new wage instead of the original one, which makes every percent increase look smaller than it is.

Procedure

Hook (5 min): Ask students how a person might earn more money in the same job without changing employers. Steer the discussion toward licenses and certifications, then explain that operators at the fictional Ravensden Water District move up a four-step ladder by passing state exams.

Direct instruction (10 min): Model a percent increase with numbers that are not on the handout. A fictional district raises an hourly wage from $16.00 to $18.00, so the raise is $2.00, and $2.00 divided by $16.00 equals 0.125, or 12.5 percent. Write "percent increase equals raise divided by original wage" on the board and ask students what answer they would get by dividing by $18.00 instead, so the wrong method is named out loud. Then model applying a raise forward: 5 percent above $18.00 is 1.05 times $18.00, or $18.90.

Guided practice (12 min): Distribute the handout. Work item 1 together, then have pairs complete items 2 and 3 and compare their two multiplications before the class moves on.

Independent practice (12 min): Students complete items 4 through 7 alone. Remind them that a full-time year on this handout is 2,080 hours, and that item 6 compares a fictional district wage with the national median given in the scenario.

Closure and exit ticket (6 min): Each student answers on an index card: "An operator's wage rises from $25.00 to $26.00 an hour. What is the percent increase?" Collect the cards. Correct work shows $1.00 divided by $25.00, giving 4 percent. Reteach the denominator if more than five students divide by $26.00.

Ravensden's Operator Pay Ladder: A Grade 7 Percent Lesson — Grade 7 Math
Name: ____________________________ Date: ______________

Student Handout

Use the fictional Ravensden Water District for every question. A full-time year at Ravensden is 2,080 hours, which is 40 hours a week for 52 weeks. The district pays operators in training $20.00 an hour and Grade 1 operators $23.00 an hour. Nationally, operators earned a median of $60,020 per year in May 2025.

  1. What is the percent increase from the $20.00 training wage to the $23.00 Grade 1 wage?
  2. A Grade 2 operator earns 10 percent more than a Grade 1 operator. What is the Grade 2 hourly wage?
  3. A Grade 3 operator earns 10 percent more than a Grade 2 operator. What is the Grade 3 hourly wage?
  4. What does a Grade 1 operator earn in a full-time year of 2,080 hours?
  5. What does a Grade 3 operator earn in a full-time year of 2,080 hours?
  6. How much less than the national median of $60,020 is that Grade 3 yearly pay?
  7. What is the percent increase from the $20.00 training wage all the way to the Grade 3 hourly wage?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 15 percent. The raise is $23.00 minus $20.00, or $3.00, and $3.00 divided by $20.00 equals 0.15.
  2. Answer: $25.30. Ten percent more than $23.00 is 1.10 times $23.00, which equals $25.30 an hour.
  3. Answer: $27.83. Ten percent more than $25.30 is 1.10 times $25.30, which equals $27.83 an hour.
  4. Answer: $47,840. Multiply the hourly wage by the hours: $23.00 times 2,080 equals $47,840 per year.
  5. Answer: $57,886.40. Multiply $27.83 by 2,080. That is $55,660 for 2,000 hours plus $2,226.40 for 80 hours, giving $57,886.40.
  6. Answer: $2,133.60. Subtract the yearly pay from the median: $60,020 minus $57,886.40 equals $2,133.60.
  7. Answer: 39.15 percent. The raise is $27.83 minus $20.00, or $7.83, and $7.83 divided by $20.00 equals 0.3915, which rounds to about 39.2 percent.

Exit ticket answer: 4 percent, because $1.00 divided by $25.00 equals 0.04.

Differentiation

Support

Give these students the ladder as a partially completed table with the training and Grade 1 wages already filled in and the multiplier 1.10 printed beside the Grade 2 and Grade 3 rows. Allow calculators and accept item 7 rounded to the nearest whole percent.

Extension

Ask students to find the single percent increase that would take the Grade 1 wage to the Grade 3 wage in one step, then explain in writing why two 10 percent raises do not add up to a 20 percent raise.

ELL supports

Pre-teach "wage," "raise," "certification," and "median" with a four-rung ladder drawing labeled with the wage at each step. Provide the frame "The raise is ___ dollars, and ___ divided by the first wage gives ___ percent" for items 1 and 7.

Extensions

Invite students to look at the four certification levels as a career path with several entry points, then write a short paragraph describing which preparation route they would choose and why, given that the job can be entered with a high school diploma and a state license or approached through a certificate program or a two-year or four-year degree.