Choosing units: cm, m, g, kg, ml and liters: what children learn
In this game children decide which unit they would use to measure everyday things, such as the length of a pencil, the mass of a bag of potatoes or the water in a bath. Choosing the right unit is the first step before estimating and measuring.
Supports part of Common Core 2.MD.A.1: choosing tools and units. This game uses metric units only, not inches, feet or pounds. This focused game does not cover the entire standard.
Common Core connection: 2.MD.A.1. This is focused practice for part of the standard.
How to play
Sort the cards into the right groups. Tap a card, then its group. You can also drag a card, or press the number on its group. Each game has 3 rounds with no timer. Every card is checked as soon as you place it: a card in the wrong group comes back with a hint, and you get a point for each card you place right first time. For a quicker go, choose Quick quiz: 10 multiple-choice questions in 150 seconds (choose Relaxed for more time).
Step by step
- What are you measuring?. Is it how long or tall something is (length), how heavy it is (mass), how much it holds (capacity) or how hot or cold it is (temperature)?
- Small or big?. Use the smaller unit for small things and the bigger unit for big things: cm for a pencil, m for a soccer pitch.
- Mass: g or kg. Grams are for light things like an apple or a letter. Kilograms are for heavier things like a bag of potatoes or a person.
- Capacity and temperature. Millilitres are for small amounts such as a spoonful of medicine; liters are for bigger amounts such as a bucket of water. Temperature is measured in degrees Celsius (°C).
Worked examples
Example 1: Which unit would you use to measure the length of a pencil?
Working: A pencil is a short length.
Answer: centimeters (cm)
Example 2: Which unit would you use for the mass of a bag of potatoes?
Working: A bag of potatoes is heavy.
Answer: kilograms (kg)
Example 3: Which unit would you use for how hot the oven is?
Working: How hot something is means temperature.
Answer: degrees Celsius (°C)
Common mistakes and how to fix them
- Using a length unit for mass, such as measuring an apple in cm. Ask first: am I measuring how long, how heavy, or how much it holds?
- Choosing meters for small things. Hold up a meter stick and a ruler. Which would you use to measure an eraser?
- Mixing up capacity and mass. Capacity is how much a container holds; mass is how heavy something is.
Activities to try at home
- Look at food packets and find the units: g, kg, ml or liters.
- Bake together and measure the ingredients with scales and a jug.
- Check the weather forecast and read the temperature in °C.
Ideas for the classroom
- Set up measuring stations with rulers, meter sticks, scales, jugs and thermometers.
- Students estimate before measuring, then compare.
- Sort real objects by which unit you would use to measure them.
Free printable game and worksheet
The free printable starts with a game sheet, such as a color-by-answer picture, an answer maze or a secret-code joke, followed by a worksheet. Both use the same checked questions as the online game, and the answers are on the last page. Print it, or save it as a PDF from your browser’s print menu.
Open the free printable game and worksheet
Frequently asked questions
How should I choose this game for my learner?
Supports part of Common Core 2.MD.A.1: choosing tools and units. This game uses metric units only, not inches, feet or pounds. This focused game does not cover the entire standard.
Can it be played with a keyboard?
Yes. Tab to a card, press Enter to pick it up, then choose the group it belongs in.