Free Grade 3 Introducing Identity Matrix Quizzes
Free Grade 3 quizzes for Introducing Identity Matrix: 12 real questions with a full answer key and worked solutions. A matrix is a grid of numbers. For a 2×2 matrix [[a, b], [c, d]], the determinant is ad − bc.
Free
Stretch
35 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify introducing identity matrix
Identify introducing identity matrix accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain introducing identity matrix
Explain introducing identity matrix accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate introducing identity matrix
Calculate introducing identity matrix accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare introducing identity matrix
Compare introducing identity matrix 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 Identity Matrix works
A matrix is a grid of numbers. For a 2×2 matrix [[a, b], [c, d]], the determinant is ad − bc.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.Find the determinant of [[-1, 0], [-1, 2]].[1]
- 2.Find the determinant of [[0, -1], [2, 1]].[1]
- 3.Find the determinant of [[3, -3], [3, 6]].[1]
- 4.Find the determinant of [[1, -4], [1, 6]].[1]
- 5.Find the determinant of [[6, -3], [1, -1]].[2]
- 6.Find the determinant of [[-3, 3], [-2, 1]].[2]
- 7.Find the determinant of [[-4, -1], [-3, 1]].[2]
- 8.Find the determinant of [[3, 1], [6, -3]].[2]
- 9.Find the determinant of [[6, -4], [-4, 4]].[3]
- 10.Find the determinant of [[0, 2], [3, 1]].[3]
- 11.Find the determinant of [[4, -4], [3, 3]].[3]
- 12.Find the determinant of [[-2, -3], [2, 3]].[3]
Show answers and working
1. -2
det = ad − bc. -1 × 2 − 0 × -1 = -2.
2. 2
det = ad − bc. 0 × 1 − -1 × 2 = 2.
3. 27
det = ad − bc. 3 × 6 − -3 × 3 = 27.
4. 10
det = ad − bc. 1 × 6 − -4 × 1 = 10.
5. -3
det = ad − bc. 6 × -1 − -3 × 1 = -3.
6. 3
det = ad − bc. -3 × 1 − 3 × -2 = 3.
7. -7
det = ad − bc. -4 × 1 − -1 × -3 = -7.
8. -15
det = ad − bc. 3 × -3 − 1 × 6 = -15.
9. 8
det = ad − bc. 6 × 4 − -4 × -4 = 8.
10. -6
det = ad − bc. 0 × 1 − 2 × 3 = -6.
11. 24
det = ad − bc. 4 × 3 − -4 × 3 = 24.
12. 0
det = ad − bc. -2 × 3 − -3 × 2 = 0.
Worked examples
Find the determinant of [[-4, -2], [-4, -3]].
- det = ad − bc.
- -4 × -3 − -2 × -4 = 4.
- Answer: 4
Find the determinant of [[1, 4], [3, 3]].
- det = ad − bc.
- 1 × 3 − 4 × 3 = -9.
- Answer: -9
Find the determinant of [[-3, 4], [0, 0]].
- det = ad − bc.
- -3 × 0 − 4 × 0 = 0.
- Answer: 0
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Calculates ab − cd.
Correction: Multiply the diagonals: ad − bc.
Gets signs wrong with negatives.
Correction: Bracket negatives before multiplying.
Teacher tips
- · Colour the two diagonals in different colours.
Parent tips
- · Point out spreadsheets as grids of numbers.
Real-life applications
- · Computer graphics, transformations.
Assessment objectives
How mastery is evidenced, and which standards it maps to.
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Frequently asked
- Is this Grade 3 Introducing Identity Matrix quiz really free?
- Yes. Every quizzes 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 Matrix Multiplication. Each one has its own free lesson, worksheet and quiz.
- How is the quiz 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 Identity Matrix?
- Move on to Working with Identity Matrix, Identity Matrix in Context, Matrix Addition, Matrix Multiplication, which build directly on this idea.
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