Math problem set Grade 4 Careers & CTE

Stony Gap Dam Operator: Multiplication, Division, and Time Problems

A grade 4 math problem set following a dam operator who controls a reservoir gate, using multiplication, division, and time to find gallons of water.

Grade: Grade 4
Subject: Careers & CTE
Material: Math problem set
Time: 40 min
Prep: No prep
Materials: None

Standards

4.OA.A.3 Common Core Math

Solve multistep word problems posed with whole numbers and having whole-number answers using the four operations, including problems in which remainders must be interpreted. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

How this material aligns: Problems 8, 9, and 10 are multistep whole-number word problems using multiplication, division with a leftover, and comparison, the reasoning this operations standard requires.

All materials for 4.OA.A.3 →

4.MD.A.2 Common Core Math

Use the four operations to solve word problems involving distances, intervals of time, liquid volumes, masses of objects, and money, including problems involving simple fractions or decimals, and problems that require expressing measurements given in a larger unit in terms of a smaller unit.

How this material aligns: Problems 4 and 6 solve liquid-volume and time word problems, including changing 3 hours into minutes, which is the measurement work this standard names.

All materials for 4.MD.A.2 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will multiply and divide whole numbers to find gallons of water released.
Students will solve multistep and leftover problems set at a reservoir dam.

Vocabulary

Reservoir: A human-made lake, usually created by a dam, that stores water for later. Reservoirs supply cities and farms and help control floods.
Dam: A strong wall built across a river to hold back water. Dams store water for people and farms, help prevent floods, and can make electricity.

Also: gate, operator, gallons

Teacher overview

The Stony Gap Reservoir (an example reservoir) sits behind a small dam. A dam operator named Mr. Alvarez controls a gate that lets water flow downstream to the town of Stony Gap. This problem set follows his week of work and uses grade 4 multiplication, division, and time. A common mistake to watch for is mixing up the time units: when a problem gives hours, students must change hours into minutes before they use a rate that is given in gallons each minute.

Stony Gap Dam Operator: Multiplication, Division, and Time Problems — Grade 4 Careers & CTE

Name: ____________________________ Date: ______________

Problems

When the gate is open, water flows out at 300 gallons each minute. Use this fact for problems 1 and 2. Show your work.

The operator opens the gate for 8 minutes. How many gallons flow out?
On another day, the operator keeps the gate open for one full hour of 60 minutes. How many gallons flow out in that hour?
On Monday the operator let out 6,000 gallons in the morning and 4,500 gallons in the afternoon. How many gallons did he let out on Monday in all?
The operator drains a small test pond that holds 9,000 gallons. He drains it evenly over 6 minutes. How many gallons drain each minute?
The operator checks the water level 4 times each day. How many checks does he make in one week of 7 days?
The dam runs a small generator for 3 hours. How many minutes is that?
The town needs 8,000 gallons of water. On a dry day the operator opens the gate only part of the way, so it lets out 1,000 gallons each hour. How many hours will it take to send 8,000 gallons?
The operator fills test jugs that each hold 4 gallons. He has 30 gallons of water. How many jugs can he fill all the way, and how many gallons are left over?
On Tuesday the operator let out 2,400 gallons. On Wednesday he let out twice as much as on Tuesday. How many gallons did he let out on Wednesday?
On Thursday the operator let out 3,000 gallons in the morning. In the afternoon he let out 1,500 gallons more than in the morning. How many gallons did he let out on Thursday in all?

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

Answer Key

Answer: 2,400 gallons. Multiply the flow rate by the minutes: 300 x 8 = 2,400 gallons.
Answer: 18,000 gallons. One hour is 60 minutes, so 300 x 60 = 18,000 gallons.
Answer: 10,500 gallons. Add the two amounts: 6,000 + 4,500 = 10,500 gallons.
Answer: 1,500 gallons each minute. Divide the pond amount by the minutes: 9,000 divided by 6 = 1,500 gallons each minute.
Answer: 28 checks. Multiply the checks per day by the days: 4 x 7 = 28 checks.
Answer: 180 minutes. One hour is 60 minutes, so 3 x 60 = 180 minutes.
Answer: 8 hours. Divide the gallons needed by the gallons each hour: 8,000 divided by 1,000 = 8 hours.
Answer: 7 full jugs with 2 gallons left over. Divide 30 by 4 to get 7 remainder 2, so 7 jugs are full and 2 gallons are left.
Answer: 4,800 gallons. Twice as much as 2,400 is 2 x 2,400 = 4,800 gallons.
Answer: 7,500 gallons. The afternoon was 3,000 + 1,500 = 4,500 gallons; add the morning: 3,000 + 4,500 = 7,500 gallons.

Differentiation

Support

Give these students a printed rule strip that shows "1 hour = 60 minutes" and a worked example of a division with a leftover before they try problem 8. Let them use base-ten blocks or a place-value chart for the larger numbers.

Extension

Ask students to find how many gallons flow out if the gate stays open for a full 2 hours at 300 gallons each minute. They must first change 2 hours into minutes, then multiply, and explain each step.

ELL supports

Pre-teach "reservoir," "dam," "gate," and "gallons" with a labeled picture of a dam and its gate. Provide the phrase "gallons each minute" on a card, and allow students to show their work with numbers and the picture rather than in full sentences.