Unit Conversion · Grades 4–9
Unit Conversion Worksheets
Metric length, mass, and capacity conversions (mm to km, mg to kg, mL to L) built from clean multiples so every conversion is exact. From Grade 5, some convert to or from a decimal, like 450 g to kg.
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What it is
Metric units scale by powers of 10, converting between them means multiplying or dividing by that scale factor, never changing the actual amount, just how it's measured. Length uses mm/cm/m/km, mass uses mg/g/kg, and capacity uses mL/L.
Why it matters
Once a student trusts that the metric system always scales by 10, they stop memorizing hundreds of separate conversion facts and just move a decimal point, one mental model instead of dozens of exceptions.
How to do it
- Identify the two units and the scale factor between them (e.g. 1 m = 100 cm).
- Converting to a SMALLER unit: multiply by the factor.
- Converting to a LARGER unit: divide by the factor.
Examples by level
- BeginnerConvert 8.79 m to cm =Answer879 cm
- IntermediateConvert 1264 cm to m =Answer12.64 m
- AdvancedConvert 30.25 km to m =Answer30250 m
Examples are generated by the same engine as the worksheets, so they're always mathematically correct. Built to avoid repeats, not reshuffle the same handful of questions.
Common mistakes
- Multiplying when the answer should be smaller (converting to a bigger unit means dividing, not multiplying).
- Losing track of how many zeros a conversion factor has (10 vs 100 vs 1000).
- Mixing up which unit is bigger, a kilogram is bigger than a gram, so 1 kg = 1000 g, not the reverse.
Tips
- Bigger unit means a smaller number for the same amount: 3 m and 300 cm are the same length.
- Every metric conversion factor is a power of 10, count the zeros to know whether to multiply or divide.
For parents
A kitchen scale or measuring cups make this concrete, weigh something in grams, then ask how many kilograms that would be.
For teachers
Anchor every conversion to the same mental model (bigger unit → divide, smaller unit → multiply) rather than teaching each unit pair as a separate rule to memorize.
Key vocabulary
- metric system
- the base-10 measurement system used for length (m), mass (g), and capacity (L)
- conversion factor
- the number you multiply or divide by to change from one unit to another
Frequently asked questions
- What grade is unit conversion taught in?
- Metric unit conversion is typically introduced in Grade 4-5 and reinforced through Grade 7 as measurements get more complex.
- Does this cover imperial units (inches, pounds, etc.)?
- Not currently, this skill covers the metric system (mm/cm/m/km, mg/g/kg, mL/L), which is the primary system taught in Canadian curricula.
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