The Customary Units of Lengths

In the fourth grade, students learn about the customary units of length. This includes determining the different customary units of length and how they are related to each other, as well as converting larger to smaller units and vice versa.

To make these measures of length lessons engaging, math teachers can employ a variety of teaching strategies. Today we bring you a few ideas for that. Use these strategies in your classroom and get your students excited about learning the customary units of length!

Strategies to Teach the Customary Units of Length

Review Length

In previous lessons, students familiarized themselves with the metric units of length, such as millimeter, centimeter, meter, and kilometer. During these lessons, they also had an introduction of what length is and how we measure how long things are by using the metric units of length.

Remind students that we define length as a measurement that determines how long an object is from one of its ends to the other. This can also mean the distance between one object and/or place to another.

In previous lessons, we answered questions about how long an object is or how far it is to get from one place to another by using the metric units of length. Point out that in this lesson, students will learn how to answer such questions by using the customary units of length.

What Are the Customary Units of Length?

Explain to students that the customary system of measurement is a set of weights and measures that we use to measure length, weight, temperature, and capacity. This system is also called the US customary system, as it’s commonly used in the US.

Point out that the customary units of length that we use are as follows:

inch
feet
yard
mile

So how can we estimate how many inches, feet, yards, or miles is something? You can provide a few examples, such as:

a regular paper clip is around one inch
the range of a large shoe is one foot
the length of a bike is about a yard
the length of a runway of an airport is around one mile

Picking the Best Unit

Point out to students that in our daily lives, we most frequently use inches, feet, and yards, whereas miles as a customary unit of length is less commonly used for everyday items. Provide a more detailed explanation for each of them:

inch (also written as “in”)
Explain that we use inches for small objects that are less than the length of a ruler. The length of a crayon can be measured using inches.
feet (also written as “ft”)

Point out that feet are exactly the size of one ruler and are used to measure bigger objects. The length of a door and the height of a person are some examples.

Yard (also written as “yd”)

Add that yard is used to measure objects that are larger than an inch or foot. The length of a football field is a good example of things measured using yards.

mile

State that miles are used to measure very large distances. This unit is best used if you want to know how far one city is from another. Just like kilometers, the distance of the Earth from the sun is measured using miles too.

Reflection:

Provide several examples of different objects or distances and ask students to reflect on them and try to guess what is the most reasonable customary unit of length that they could use for each measuring length/distance in each specific case. For instance:

the length of a banana?
the height of a basketball player?
the length of a room?
the distance ran in a marathon?

The Customary Units of Lengths: Conversion Chart

Point out to students that we can convert the different customary units of length from one unit to another, including from larger units to smaller ones, as well as from smaller units to larger ones. You can create a conversion chart like the one below that students can refer to for this purpose:

Converting Measures of Length from Larger to Smaller Units

Remind students that when we were performing conversions of larger units of lengths to smaller ones in lessons on the metric units of length, we used multiplication. We will apply the same operation here. And we’ll always refer to the conversion chart to convert.

Provide a few examples of how this is done in practice. You can start with the easiest conversions, such as changing feet to inches. For instance:

5 feet = __inches?

Start by looking at the conversion chart above. Based on it, we know that 1 foot equals 12 inches. To find out how many inches is 5 feet, we’ll simply multiply the value of feet by 12:

5 feet = __inches?

1 feet = 12 inches

5 × 12 = 60 inches

5 feet = 60 inches

Provide a second example. For instance, demonstrate to children how to convert miles to yards.

Write such a conversion problem on the whiteboard, for example:

2 miles = __ yards?

Highlight that we’ll look at the conversion chart again and check how many yards equals 1 mile. We can observe that 1 mile is equivalent to 1,760 yards. To find out the answer to our question, we need to multiply the value of miles by 1,760, that is:

2 miles = __ yards?

1 mile = 1,760 yards

2 × 1,760 = 3,520 yards

2 miles = 3,520 yards

Converting Measures of Length from Smaller to Larger Units

Remind students that when we were performing conversions of smaller units to larger ones in our lessons on the metric units of length, we used division. We will apply the same operation here. And we’ll always refer to the conversion chart to convert.

Provide a few examples of how we perform this in practice. You can start with the easiest conversions, such as changing inches to feet. For instance:

24 inches = __feet?

Explain that in this case as well, we start by looking at the conversion chart above. Based on it, we can observe that 1 inch equals 1/12 of a foot. To find out how many feet is equivalent to 24 inches, we’ll divide the value of inches by 12:

24 inches = __feet?

1 inch = 1/12 foot

24/12 = 2 feet

24 inches = 2 feet

Provide a second example. For instance, demonstrate to children how to convert yards to miles.

Write such a conversion problem on the whiteboard, for example:

3,520 yards = __miles?

Point out that we’ll look at the conversion chart again. We can observe that 1 yard is equivalent to 1/1,760 of a mile. To find out the answer to our question, we need to divide the value of yards by 1,760, that is:

3,520 yards = __miles?

1 yard = 1/1,760 miles

3,520/1/1,760 = 2 miles

3,520 yards = 2 miles?

Additional Resources

If you have the technical means in your classroom, you can also complement your lesson with multimedia materials, such as videos. For instance, you can use this video to introduce the different customary units of length.

The video contains step-by-step instructions, as well as examples on how to convert larger to smaller units, as well as smaller to larger units. Review length and then play the video. Allow time for questions.

Activities to Practice the Customary Units of Length

Broken Hearts Conversion Game

This game will help students practice their knowledge of customary units of length, and more specifically, converting larger to smaller units and vice versa. To use this activity in your classroom you’ll need scissors and red construction paper.

Draw plenty of hearts on the construction paper and cut them in half. Write one customary unit of length on one half and another customary unit of length on the other half. For instance, if you write 30 yards on one half, you could write 90 feet.

Mix up the halves in a pile. Create several such piles, depending on the number of students. Divide students into groups of 3 or 4 and hand out one pile of ‘broken hearts’ to each group. Provide instructions for the game.

Explain to students that they have to match each half heart with a half heart that contains an equivalent customary unit of length. The group that manages to correctly match all the hearts first wins the game. Homeschooling parents can adjust the game as an individual activity.

Estimating Length Game

This game will help students practice their skills at estimating length by using the customary units of length. To implement this activity in your classroom, you’ll need a number of technical devices such as laptops or phones (one per student).

This is an individual game, so it’s also suitable for homeschooling parents. Explain to students that they will play a game involving several questions on estimating length, for instance: ‘what is the most reasonable unit to measure the distance of a flight?’

In each question, students are offered multiple answers and they need to select the correct answer. If they get stuck, they can also choose to use a hint or watch a video for help. Provide time for reflection and discussion after the students finish the game.

Before You Leave…

This article outlined a few useful strategies on how to teach the customary units of length to fourth graders. If you liked these strategies and you’re interested in more math resources for children of all ages, sign up for loads of free content!

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This article is based on:

Unit 8 – Unit Conversion and Measurement