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Lesson plan Grade 4 Math

A Day with a Water Plant Operator: Grade 4 Water Math

A 45-minute grade 4 lesson following a fictional plant operator's shift, where students solve multistep tank and delivery problems and interpret a remainder.

Objectives

  1. Students will solve multistep water problems using multiplication, subtraction, and division.
  2. Students will interpret a remainder in a real water plant setting.
  3. Students will describe what a water treatment plant operator does during a shift.

Vocabulary

Key words: operator, shift, remainder, license

Teacher overview

This lesson follows Mr. Ortega, an operator at the fictional Coppertown water plant, through part of his shift as he checks tanks, records gallons, and packs water samples. The math is grade 4 multistep work: multiply, subtract, and divide with a remainder to interpret. The lesson also introduces the operator career honestly, noting that people reach it by different routes, from a high school diploma with on-the-job training and a state license, through certificate programs and engineering degrees. A common misconception is that a leftover amount in a division problem can always be dropped; handout problem 5 shows a case where the leftover still needs to be handled.

Procedure

Hook (5 min): Ask students what a person who runs a water plant does all day. Take three or four ideas, then explain that an operator keeps the water safe and moving, and that today the class will do the same math the operator uses. Name the operator Mr. Ortega and the plant Coppertown.

Direct instruction (10 min): Model one problem on the board without using any handout numbers. Say: a tank holds 800 gallons, the operator adds 300, then removes 250. Work it left to right, 800 + 300 = 1,100, then 1,100 − 250 = 850 gallons. Circle each step and label it, so students see that a multistep problem is solved one step at a time. Mention that operators reach the job by several education paths and that all of them are respected.

Guided practice (10 min): As a class, solve one division problem with a remainder: 26 sample bottles packed 4 to a tray gives 6 trays and 2 bottles left. Ask students what the class should do with the 2 leftover bottles, and guide them to see that the bottles still need a tray, so a seventh tray is needed. This sets up the handout.

Independent practice (15 min): Students complete problems 1 through 5 on the Student Handout on their own or in pairs. Circulate and check that each student shows every step, not just a final number.

Closure and exit ticket (5 min): Students answer handout problem 6 on their own and hand it in. Scan the exit answers: a student who reaches 750 gallons has done both steps correctly. Reteach the next day if more than a third of the class misses it.

A Day with a Water Plant Operator: Grade 4 Water Math — Grade 4 Math
Name: ____________________________ Date: ______________

Student Handout

Mr. Ortega works a shift at the Coppertown water plant. Solve each problem. Show every step.

  1. The plant has 3 tanks. Each tank holds 500 gallons. How many gallons is that in all?
  2. A tank holds 1,500 gallons. Mr. Ortega drains 1,200 gallons. How many gallons are left?
  3. A truck brings 6 barrels. Each barrel has 55 gallons. How many gallons did the truck bring?
  4. The plant used 1,464 gallons over 6 days, the same amount each day. How many gallons per day?
  5. Mr. Ortega packs 50 sample bottles, 8 to a tray. How many full trays are there, and how many bottles are left over?
  6. A tank has 900 gallons. Mr. Ortega adds 250 gallons, then removes 400 gallons. How many gallons are in the tank now?

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: 1,500 gallons. 3 tanks × 500 gallons = 1,500 gallons.
  2. Answer: 300 gallons. 1,500 − 1,200 = 300 gallons left.
  3. Answer: 330 gallons. 6 barrels × 55 gallons = 330 gallons.
  4. Answer: 244 gallons per day. 1,464 ÷ 6 = 244, with no remainder.
  5. Answer: 6 full trays, 2 bottles left over. 50 ÷ 8 = 6 remainder 2, since 8 × 6 = 48 and 50 − 48 = 2; the 2 leftover bottles would need one more tray.
  6. Answer: 750 gallons. 900 + 250 = 1,150, then 1,150 − 400 = 750 gallons.

Differentiation

Support

Give students a step tracker with three labeled boxes so they can write each step of a multistep problem in order. Provide the multiplication facts for 55 and the divisor in problem 4. Let students use base-ten blocks for the division.

Extension

Ask students to write their own three-step tank problem for Mr. Ortega that starts at 900 gallons and ends at exactly 500 gallons, then trade with a partner to solve and check.

ELL supports

Pre-teach "operator," "tank," "drain," and "tray" with simple pictures. Provide sentence frames for showing work: "First I ___. Then I ___. The answer is ___ gallons."

Extensions

Invite the class to write a short set of questions for a real water plant operator, such as how many tanks the local plant has and how an operator earns a license, and send the questions to the town's public works department as a class letter.