E2.2 Use metric prefixes to describe the relative size of different metric units, and choose appropriate units and tools to measure length, mass, and capacity.
Activity 1: Using Metric Prefixes
Complete the following table.
| Metric Prefix | kilo- | deca- | No prefix | centi- | milli- | ||
|---|---|---|---|---|---|---|---|
| Unit Value | 100 units | 10 units | 1 unit | \(\frac{1}{10}\) unit | \(\frac{1}{1000}\) unit | ||
| Place Value | thousand | hundred | one | one tenth | one hundredth |
Source: The Ontario Curriculum. Mathematics, Grades 1-8 Ontario Ministry of Education, 2020.
Activity 2: Choosing the Appropriate Unit and Measurement Tool
Present the illustration below to the students. Sample questions to ask include:
- What could be measured in this illustration? What attribute (length, mass, or capacity) is involved?
- What would be the most appropriate unit to measure this attribute?
- What measuring tool could be used to measure this attribute?
Ask students to explain their reasoning.
Activity 3: Referring to Unit!
Ask students to find an object at school or at home that has a length of one metre, an object that has a mass of one gram, and a container that has a capacity of one litre. Remind them that these measurements represent the base unit for length, mass, and capacity. Then ask them questions such as:
- Using the metre unit, represent a decametre. How many metres are needed to represent it?
- How many objects with a mass of one gram are needed to represent a mass of one hectogram? (Suggest that students represent a mass of one hectogram if it is possible to have 100 objects of one gram). Do you know any objects that have an approximate mass of one hectogram?
- Into how many equal parts must the litre be divided to obtain parts of a centilitre? a millilitre?