Add-Subtract Mixed Standard Units


Our Add-Subtract Mixed Standard Units lesson plan helps students add and subtract measurements with standard units. This lesson will give students a chance to practice using the standard units of measure for distance, capacity, and weight/mass.

Included with this lesson are some adjustments or additions that you can make if you’d like, found in the “Options for Lesson” section of the Classroom Procedure page. One of the optional additions to this lesson is to have your students weigh their backpacks and then add and subtract each measurement.

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What our Add-Subtract Mixed Standard Units lesson plan includes

Lesson Objectives and Overview: Add-Subtract Mixed Standard Units teaches students how to add and subtract measurements that have different standard units. The standard or customary system is the measurement system most commonly used in the United States, so it’s important for students to be familiar with it. By the end of the lesson, students will be able to convert between different units of measurement. This lesson is for students in 4th grade and 5th grade.

Classroom Procedure

Every lesson plan provides you with a classroom procedure page that outlines a step-by-step guide to follow. You do not have to follow the guide exactly. The guide helps you organize the lesson and details when to hand out worksheets. It also lists information in the blue box that you might find useful. You will find the lesson objectives, state standards, and number of class sessions the lesson should take to complete in this area. In addition, it describes the supplies you will need as well as what and how you need to prepare beforehand. The only supplies you will need for this lesson is measuring tape.

Options for Lesson

Included with this lesson is an “Options for Lesson” section that lists a number of suggestions for activities to add to the lesson or substitutions for the ones already in the lesson. One optional addition to this lesson is to have your students weigh their backpacks and then add and subtract each measurement. You can also have them pour different amounts of liquids and then measure them. Finally, have students practice their conversions by drawing their own charts.

Teacher Notes

The teacher notes page includes lines that you can use to add your own notes as you’re preparing for this lesson.


Add/Subtract Mixed Standard Units

The Add-Subtract Mixed Standard Units lesson plan includes two content pages. The standard system of measurement is the system most commonly used in the United States. We don’t have a predictable way to relate the measurements to one another with this system. The products you buy are most often in the US standard system. Manufacturing also uses this system.

Standard Units Chart

The lesson includes the standard unites and conversions for distance, capacity, and weight/mass, listed in a helpful chart, split into length, weight, capacity, and time.

Sometimes, however, the measurements aren’t perfect and you need to add or subtract standard units that have both feet and inches or both quarts and gallons. The lesson walks through a few examples of this and how to handle them.

Let’s say we need to add two different measurements: 2 ft 5 in + 4 ft 3 in. First, we line up the units from largest to smallest and then add the corresponding measurements (feet with feet and inches with inches). We add the feet: 2 + 4 = 6. Next, we add the inches: 5 + 3 = 8. Then put them together, and the final answer is 6 ft 8 in.

You might sometimes need to convert, like with the problem 1 gal 3 qts + 5 gal 2 qts. We add the gallons and the quarts to find an answer of 6 gal 5 qts. However, 4 qts = 1 gal, so we convert 4 of the quarts into a gallon, for a final answer of 7 gal 1 qt.

The lesson closes with a final example problem to help solidify students’ understanding of the material.


The Add-Subtract Mixed Standard Units lesson plan includes four worksheets: an activity worksheet, a practice worksheet, a homework assignment, and a quiz. You can refer to the guide on the classroom procedure page to determine when to hand out each worksheet.


For the activity worksheet, students will measure the height of each student in the class in feet and inches, writing each measurement on an index card. They will then pair up to find both the sum and difference of their heights. If you have enough time, students can compare their height with multiple other students’.


The practice worksheet asks students to solve eight problems using the approximate vehicle weights listed on the first page of the worksheet.


For the homework assignment, students will create their own set of three addition and three subtraction problems using a table of measurements that they either create themselves or find online.


This lesson also includes a quiz that you can use to test students’ understanding of the lesson material. For the quiz, students will solve two problems that require them to add or subtract mixed standard units.

Worksheet Answer Keys

This lesson plan includes answer keys for the practice worksheet and the quiz. If you choose to administer the lesson pages to your students via PDF, you will need to save a new file that omits these pages. Otherwise, you can simply print out the applicable pages and keep these as reference for yourself when grading assignments.

Additional information


4th Grade, 5th Grade



State Educational Standards

None for Grade 4, LB.Math.Content.5.MD.A.1

Lessons are aligned to meet the education objectives and goals of most states. For more information on your state objectives, contact your local Board of Education or Department of Education in your state.