Lesson plan Grade 6 Math

Colton Street Main: A Grade 6 Flow-Splitting Ratio Lesson

A 45-minute grade 6 math lesson where a fictional water main splits flow in a 2-to-1 ratio, so students share gallons per minute and find each pipe's percent.

Grade: Grade 6
Subject: Math
Material: Lesson plan
Time: 45 min
Prep: Low prep
Materials: Printed flow-split handout, Index cards

Standards

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: In the guided practice and handout, students split a total flow by a 2-to-1 ratio and find each pipe's percent of the flow, the ratio and percent work this standard targets.

All materials for 6.RP.A.3 →

6.RP.A.1 Common Core Math

Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities. For example, 'The ratio of wings to beaks in the bird house at the zoo was 2:1, because for every 2 wings there was 1 beak.'

How this material aligns: The direct instruction has students describe the split with ratio language, saying two parts go one way for every one part the other, exactly the ratio concept this standard defines.

All materials for 6.RP.A.1 →

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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 split a total flow into parts using a given ratio and describe the split in ratio language.
Students will find what percent of the total flow each pipe carries.

Vocabulary

Water main: A big underground pipe that carries drinking water beneath the streets to a neighborhood. Smaller service lines branch off it to reach each building.

Also: ratio, flow, percent

Teacher overview

A large water pipe, called a main, often splits into smaller pipes that feed different neighborhoods. When it splits, the flow does not always divide evenly; it divides in a ratio set by the pipe sizes and the demand each side pulls. This lesson uses that split as a concrete setting for ratio and percent work. Colton Street is a fictional main created for this lesson. A common misconception is that a split is always 50-50; students should learn to read the ratio and share the total by parts, then check that the parts add back to the whole.

Procedure

Hook (5 min): Draw one thick pipe splitting into two thinner pipes on the board. Ask students to guess how the water divides between the two branches, and record their guesses, most of which will assume an even split.

Direct instruction (12 min): Introduce the fictional Colton Street main, which carries 600 gallons each minute and splits in a 2-to-1 ratio. Model the "parts" method: 2 parts plus 1 part is 3 equal parts, so one part is 600 divided by 3, which is 200 gallons per minute. Pipe A gets 2 parts, or 400; Pipe B gets 1 part, or 200. Check that 400 plus 200 returns the 600 total. Use ratio language aloud: two parts flow to Pipe A for every one part to Pipe B.

Guided practice (13 min): As a class, find what percent of the flow each pipe carries. Pipe A is 400 of 600, which students simplify and convert to a percent; Pipe B is 200 of 600. Stress that the two percents add to 100.

Independent practice (10 min): Students complete the Student Handout on their own, checking with a partner after item 4.

Closure and exit ticket (5 min): On an index card, students answer: a main carries 900 gallons each minute in a 2-to-1 split; how many gallons per minute go to the 2-part pipe? Collect and scan for the parts method before dismissal.

Colton Street Main: A Grade 6 Flow-Splitting Ratio Lesson — Grade 6 Math

Name: ____________________________ Date: ______________

Student Handout

Suppose the fictional Colton Street main carries 600 gallons each minute. It splits into two pipes. Pipe A and Pipe B share the water in a 2-to-1 ratio. Use these numbers for the questions below.

In a 2-to-1 split, how many equal parts are there in all?
How many gallons per minute is one part?
How many gallons per minute go to Pipe A, which gets 2 parts?
How many gallons per minute go to Pipe B, which gets 1 part?
What percent of the total flow goes to Pipe A?
On a hot day the main carries 900 gallons each minute at the same 2-to-1 split. How many gallons per minute go to Pipe A?

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: 3 parts. A 2-to-1 split has 2 + 1 = 3 equal parts.
Answer: 200 gallons per minute. One part is 600 ÷ 3 = 200 gallons per minute.
Answer: 400 gallons per minute. Pipe A gets 2 parts: 2 × 200 = 400 gallons per minute.
Answer: 200 gallons per minute. Pipe B gets 1 part: 1 × 200 = 200 gallons per minute.
Answer: 67%. Pipe A carries 400 of 600, and 400 ÷ 600 = 0.667, or about 67 percent.
Answer: 600 gallons per minute. One part is 900 ÷ 3 = 300, and Pipe A gets 2 parts: 2 × 300 = 600 gallons per minute.

Differentiation

Support

Give students three connected boxes to represent the three parts, so they can write the one-part value in each box and then group two boxes for Pipe A. Work item 2 together, and allow a calculator for the percent in item 5.

Extension

Ask students to find each pipe's share if the same main, carrying 600 gallons each minute, split in a 3-to-1 ratio instead, and to explain in ratio language how the change moves water from one pipe to the other.

ELL supports

Pre-teach main, split, part, and share with a simple drawing of one pipe branching into two. Provide a sentence frame: "There are ___ parts, so one part is ___ gallons per minute." Allow labeled number sentences instead of full sentences.