Free Grade 3 Introducing Imaginary Unit Lesson Plans
Free Grade 3 lesson plans for Introducing Imaginary Unit: 12 real questions with a full answer key and worked solutions. Metric units change by powers of 10: 10 mm in a cm, 100 cm in a m, 1000 m in a km. Multiply to convert to a smaller unit, divide to convert to a bigger one.
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35 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain introducing imaginary unit
Explain introducing imaginary unit accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate introducing imaginary unit
Calculate introducing imaginary unit accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare introducing imaginary unit
Compare introducing imaginary unit accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify introducing imaginary unit
Justify introducing imaginary unit accurately in a familiar context.
Assessed by: Exit ticket of four short items
Prerequisites
Close these gaps first — each has its own free lesson, worksheet and quiz.
How Introducing Imaginary Unit works
Metric units change by powers of 10: 10 mm in a cm, 100 cm in a m, 1000 m in a km. Multiply to convert to a smaller unit, divide to convert to a bigger one.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.Convert 3 m to cm.[1]
- 2.Convert 6 L to mL.[1]
- 3.Convert 4 L to mL.[1]
- 4.Convert 3 kg to g.[1]
- 5.Convert 1.7 cm to mm.[2]
- 6.Convert 7.7 kg to g.[2]
- 7.Convert 7.7 m to cm.[2]
- 8.Convert 8.2 cm to mm.[2]
- 9.Convert 9.9 kg to g.[3]
- 10.Convert 6.3 kg to g.[3]
- 11.Convert 5.1 kg to g.[3]
- 12.Convert 4.5 L to mL.[3]
Show answers and working
1. 300 cm
1 m = 100 cm. 3 × 100 = 300 cm.
2. 6000 mL
1 L = 1000 mL. 6 × 1000 = 6000 mL.
3. 4000 mL
1 L = 1000 mL. 4 × 1000 = 4000 mL.
4. 3000 g
1 kg = 1000 g. 3 × 1000 = 3000 g.
5. 17 mm
1 cm = 10 mm. 1.7 × 10 = 17 mm.
6. 7700 g
1 kg = 1000 g. 7.7 × 1000 = 7700 g.
7. 770 cm
1 m = 100 cm. 7.7 × 100 = 770 cm.
8. 82 mm
1 cm = 10 mm. 8.2 × 10 = 82 mm.
9. 9900 g
1 kg = 1000 g. 9.9 × 1000 = 9900 g.
10. 6300 g
1 kg = 1000 g. 6.3 × 1000 = 6300 g.
11. 5100 g
1 kg = 1000 g. 5.1 × 1000 = 5100 g.
12. 4500 mL
1 L = 1000 mL. 4.5 × 1000 = 4500 mL.
Worked examples
Convert 4 cm to mm.
- 1 cm = 10 mm.
- 4 × 10 = 40 mm.
- Answer: 40 mm
Convert 5.3 km to m.
- 1 km = 1000 m.
- 5.3 × 1000 = 5300 m.
- Answer: 5300 m
Convert 6.5 km to m.
- 1 km = 1000 m.
- 6.5 × 1000 = 6500 m.
- Answer: 6500 m
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Divides when converting to a smaller unit.
Correction: Smaller units mean more of them — multiply.
Uses 100 for every conversion.
Correction: Learn which pairs use 10, 100 or 1000.
Teacher tips
- · Keep a conversion staircase on the wall.
Parent tips
- · Weigh fruit at the shop and convert kg to g.
Real-life applications
- · Cooking, measuring height, reading road signs.
Assessment objectives
How mastery is evidenced, and which standards it maps to.
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Frequently asked
- Is this Grade 3 Introducing Imaginary Unit lesson plan really free?
- Yes. Every lesson plans on FreeMathWorksheet is free to use, print and share — no account, no paywall and no watermark.
- What should a learner already know before this?
- Start with Real Numbers. Each one has its own free lesson, worksheet and quiz.
- How is the lesson plan sequenced?
- Recognition first, then understanding, application, reasoning and finally mastery — the same ladder used across every free resource on the platform.
- What comes next after Introducing Imaginary Unit?
- Move on to Working with Imaginary Unit, Imaginary Unit in Context, Argand Diagram, Complex Arithmetic, which build directly on this idea.
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