Combine Mass Measurements with Matching Units

Supplied materials

• Paper and a pencil; drawing and spoken explanations are welcome. An adult may read directions and options aloud.
• Supplied worked-case record: A model bag has 240 g of blue counters and 180 g of red counters.
• All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

Mass tells how much matter an object has and can be recorded in grams or kilograms. In this lesson inputs use the same unit within each calculation. Add masses when objects are combined and subtract to compare. A count of objects alone does not give total mass.

Read the stated mass unit and operation needed. Combine or compare only measurements in that unit. Write the unit with the result and use an inverse operation to check the arithmetic.

Keep the same mass unit throughout the calculation. Do not introduce an unstated container mass into this supplied model. Write each mass beside a separate model group and label the combined mass.

1. Write each mass beside a separate model group and label the combined mass.
2. Follow the worked example. Point to each number or shape feature and say what it tells you.
3. Read the stated mass unit and operation needed.
4. Try the question and then the three practice questions. Check your answers and explain any change you make.

Check your reasoning

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Take it further

A 650 g group loses a 275 g part. Expected: 375 g remain.

Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.