Math problem set Grade 4 Math

Ashford Pump Station: Gallons and Minutes Multiplication

A grade 4 problem set at the fictional Ashford pump station, using multi-digit multiplication to find total gallons pumped from a flow in gallons per minute.

Grade: Grade 4
Subject: Math
Material: Math problem set
Time: 35 min
Prep: No prep
Materials: None

Standards

4.NBT.B.5 Common Core Math

Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.

How this material aligns: Problems 1 through 5 and 7 multiply a two- to four-digit flow by a one- or two-digit number of minutes, with an area model in problem 7, as this standard requires.

All materials for 4.NBT.B.5 →

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 and 9 are multistep word problems that combine two pump runs and compare two pumps, using multiplication with addition and subtraction as this standard describes.

All materials for 4.OA.A.3 →

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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 a flow in gallons per minute by a number of minutes to find total gallons.
Students will solve multistep problems that combine or compare two pumps.

Vocabulary

Key words: flow, product, area model

Teacher overview

The fictional town of Ashford runs a pump station with three pumps, each moving a set number of gallons each minute. This set has students find total gallons by multiplying a flow by a number of minutes, using the multi-digit multiplication of 4.NBT.B.5 and the multistep reasoning of 4.OA.A.3. Problems 2, 4, 6, and 8 reuse the pump flows given in problems 1 and 3, so students should work in order. A common error is adding the flow and the minutes instead of multiplying them; remind students that a rate repeated over many minutes calls for multiplication, not addition.

Ashford Pump Station: Gallons and Minutes Multiplication — Grade 4 Math

Name: ____________________________ Date: ______________

Problems

The town of Ashford runs a pump station. Each pump moves the same number of gallons each minute in every problem. Find the total gallons.

Pump A moves 40 gallons each minute. How many gallons does it move in 6 minutes?
Pump A runs for 30 minutes. How many gallons is that in all?
Pump B moves 125 gallons each minute. How many gallons in 8 minutes?
Pump B runs for 7 minutes. How many gallons is that?
Pump C moves 1,200 gallons each minute. How many gallons in 5 minutes?
Pump A and Pump B each run for 1 minute. How many gallons do they move together?
Draw an area model for 40 × 6. What is the product?
Pump A runs for 15 minutes, then 15 minutes more. How many gallons in all?
In 4 minutes, which pump moves more, Pump A at 40 gallons each minute or Pump B at 125 gallons each minute? By how many gallons?

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: 240 gallons. 40 × 6 = 240 gallons.
Answer: 1,200 gallons. 40 × 30 = 1,200 gallons.
Answer: 1,000 gallons. 125 × 8 = 1,000 gallons.
Answer: 875 gallons. 125 × 7 = 875 gallons.
Answer: 6,000 gallons. 1,200 × 5 = 6,000 gallons.
Answer: 165 gallons. Pump A moves 40 and Pump B moves 125 in one minute, so 40 + 125 = 165 gallons.
Answer: 240 gallons. Students may draw a rectangle labeled 6 by 40 and write 240 inside, since 40 × 6 = 240.
Answer: 1,200 gallons. 15 + 15 = 30 minutes, and 40 × 30 = 1,200 gallons.
Answer: Pump B, by 340 gallons. Pump A moves 40 × 4 = 160 gallons and Pump B moves 125 × 4 = 500 gallons, so B moves 500 − 160 = 340 more gallons.

Differentiation

Support

Give students a printed area-model grid and a multiplication chart. Start with problems 1 and 3, which use a one-digit number of minutes, before the two-digit problems. Let students break 30 minutes into 3 tens when they multiply in problem 2.

Extension

Ask students to find how many minutes Pump B must run to move exactly 1,000 gallons if it moves 125 gallons each minute, then check the answer by multiplying back.

ELL supports

Provide a labeled picture of a pump with an arrow showing water moving out each minute. Give a sentence frame for the word problems: "The pump moves ___ gallons each minute for ___ minutes, so I multiply to get ___ gallons."