Converting feet to yards and grams to kilograms
In 5th grade, children learn to convert between units in the same system, like feet to yards or grams to kilograms, and to use conversions in multi-step problems.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 5th grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
Nadia asks for 3/4 pound of sliced turkey at the deli. How many ounces of turkey is that?
- 4 ounces
- 9 ounces
- 12 ounces
Why this matters
From cooking and buying paint to reading medicine doses and planning a trip, converting units is something your child will do for life. It also sets up the ratio and rate work of 6th grade, where changing units is a central step, and science classes, where an answer in the wrong unit counts as wrong. Knowing when to multiply and when to divide is the key part.
Where kids can get stuck
- Dividing when they should multiply, so 4 yards becomes 4 ÷ 3 feet instead of 4 × 3 = 12 feet.
- Treating feet and inches like decimals, writing 5 feet 8 inches as 5.8 feet instead of 5 2/3 feet.
- Forgetting to convert back at the end, answering 96 ounces when the question asked for pounds, which is 6.
How you can help
- Read package sizes at the grocery store and convert them together: a 2-pound bag of rice is how many ounces? A 2-liter bottle is how many milliliters? Ask your child to explain whether to multiply or divide.
- Measure your child's height in inches with a tape measure, then ask them to write it in feet and inches. For example, 56 inches is 4 feet 8 inches.
- Plan a craft or garden project that needs conversions, such as cutting 2 yards of string into 8-inch pieces. Ask your child how many pieces you can cut, which is 9, with no string left over.
If it’s helpful, you can sign up for free, adaptive practice in Bobby's Math Club.
Questions parents ask
Why is my child learning measurement conversions this way?
Teachers want your child to understand why conversions work, not only memorize tables. If 1 yard is 3 feet, then 4 yards must be 4 groups of 3 feet. Reasoning about the size of units helps your child decide whether to multiply or divide. Multi-step problems show how conversions are used in everyday tasks like cooking, building, and shopping.
Does my child need to memorize all the conversion facts?
It helps to know the common ones, such as 12 inches in a foot, 3 feet in a yard, 16 ounces in a pound, 4 quarts in a gallon, and 100 centimeters in a meter. Many teachers provide a reference chart for less common facts. The bigger skill is knowing how to use a conversion fact once your child has it.
Why is the metric system easier for my child?
Metric units are related by 10, 100, and 1,000, so converting is like shifting digits in place value. For example, 3.5 kilograms is 3,500 grams. Customary units use numbers like 12, 3, and 16, which take more calculation. Both are taught because both are used, and working with each strengthens a different part of your child's number sense.
Make learning math fun
Bobby's Math Club turns 5th grade math practice into something fun to do together.
- Free, unlimited practice for every child in your family
- A few minutes a day, at just the right level
- Hints when they are stuck, and a celebration when it clicks
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
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Join the clubNote for teachers: This skill is covered by Common Core math standard 5.MD.A.1: “Convert among different-sized standard measurement units within a given measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions in solving multi-step, real world problems.” Learn how Bobby's Math Club can help your students grow. (Common Core 5.MD.1)