4th Grade Measurement Units and Conversions Lesson: Notes and Examples (Free PDF)

4th grade measurement conversions lesson – Maths PDF

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This 4th grade measurement conversions lesson covers measurement units and conversions (Common Core 4.MD.A.1, 4.MD.A.2), with a free PDF to print.

Key takeaway: This lesson helps fourth grade students convert between larger and smaller units of length, mass, liquid volume, weight, and time, and use those conversions to solve problems.

Topic: Measurement Units and Conversions (4th grade)
Content: One-page lesson with a definition, a worked example and key facts
Standards: 4.MD.A.1, 4.MD.A.2
Answers: Explanations included
Format: Free printable PDF, US Letter, black and white

Measurement units tell how long, how heavy, or how much liquid something is. To change a larger unit into a smaller unit, multiply by the number of small units in one large unit. For example, 1 kilometer is 1,000 meters, so 3 km is 3,000 m. Smaller units give bigger numbers.

This lesson helps fourth grade students convert between larger and smaller units of length, mass, liquid volume, weight, and time, and use those conversions to solve problems. Also, it shows why changing a larger unit to a smaller unit means multiplying, using double number lines and tables.

Students learn the key facts: 1 kilometer is 1,000 meters, 1 meter is 100 centimeters, 1 kilogram is 1,000 grams, 1 liter is 1,000 milliliters, 1 pound is 16 ounces, and 1 hour is 60 minutes. They also work with mixed units like 3 hours 20 minutes. Then, plan about 25 minutes, and write each fact on a card.

Grade 4 · Common Core State Standards: 4.MD.A.1, 4.MD.A.2

Key facts in this 4th grade measurement conversions lesson

Key facts

1 km = 1,000 m and 1 m = 100 cm.
1 kg = 1,000 g and 1 L = 1,000 mL.
1 lb = 16 oz, 1 hr = 60 min, and 1 min = 60 sec.
Larger unit to smaller unit: multiply, and the number gets bigger.
Change both amounts to the same unit before you add or subtract.

What are measurement units?

Every measurement has a number and a unit. The unit tells what you are counting: kilometers for long trips, grams for light things, milliliters for small amounts of liquid, minutes for time. One amount can be written in different units, just like one dollar can be four quarters.

Going from a larger unit to a smaller unit means multiplying.

Unit facts to know

What we measure	Larger unit	Smaller unit
Length	1 km	1,000 m
Length	1 m	100 cm
Mass	1 kg	1,000 g
Liquid volume	1 L	1,000 mL
Weight	1 lb	16 oz
Time	1 hr	60 min
Time	1 min	60 sec

How do you change a larger unit into a smaller unit?

A small unit is tiny, so you need many of them to match one big unit. That is why you multiply. Look at the bar: one kilogram is a block of 1,000 grams, and 2 kilograms are two blocks.

Each block is 1 kg = 1,000 g.

So \(2\text{ kg} = 2 \times 1{,}000 = 2{,}000\text{ g}\). Time works the same way. The double number line shows that 3 hours match 180 minutes.

Each hour matches 60 minutes.

How do you solve a measurement word problem?

Write every amount in the same unit first. Then add, subtract, or multiply.

Example. Liam bikes 2 km 600 m to school and the same way home. How many meters does he bike in all?

Change 2 km to meters: \(2 \times 1{,}000 = 2{,}000\text{ m}\).
Add the extra meters: \(2{,}000 + 600 = 2{,}600\text{ m}\) one way.
Two trips: \(2 \times 2{,}600 = 5{,}200\text{ m}\).

Liam bikes 5,200 m, which is 5 km 200 m. For time, remember that minutes roll over at 60: 1 hr 45 min is 60 + 45 = 105 min.

Mark: 1 hr 45 min is 105 minutes.

4th grade measurement conversions lesson: questions and answers

What is the difference between metric and customary units?

Kilometers, meters, centimeters, kilograms, grams, liters, and milliliters are metric units, and they use 10, 100, and 1,000. Pounds and ounces are customary units, and 1 pound is 16 ounces.

Why do you multiply to change a larger unit to a smaller unit?

A smaller unit fits many times into a larger one. If 1 km holds 1,000 m, then 5 km holds 5 groups of 1,000 m, so you multiply 5 by 1,000.

How do you write 3 hr 20 min in minutes?

Change the hours first: 3 hr is 3 × 60 = 180 min. Then add the extra 20 minutes to get 200 minutes.

How do you add measurements that use different units?

Change them to the same unit before adding. For example, add 2 kg and 500 g by writing 2 kg as 2,000 g, then 2,000 + 500 = 2,500 g.

How many ounces are in a pound?

There are 16 ounces in 1 pound. So 2 pounds are 2 × 16 = 32 ounces, and 4 pounds are 64 ounces.

Common mistakes with this 4th grade measurement conversions lesson

Students divide when changing a larger unit to a smaller one. Four kilometers is a bigger number of meters, so multiply by 1,000 to get 4,000 meters.
Students mix up customary and metric facts, such as using 100 for ounces in a pound. A pound is 16 ounces, so check the unit fact before you multiply.
Students convert only the larger part of a mixed measurement. In 2 meters 35 centimeters, change 2 meters to 200 centimeters, then add the 35.

How to study this chapter

Before converting, ask which unit is bigger. If you go from big to small, the number must grow, so check that your answer is larger.
Make a conversion card with the six key facts and keep it beside you. Finally, after a week of practice, most students remember them without it.
Parents can use a measuring cup and a kitchen scale to show liters, milliliters, pounds, and ounces in a recipe.

Download the 4th grade measurement conversions lesson as a PDF with the button below and keep it with your notes.