3B · Chapter 8 · consolidation
Practice B
Original cumulative chapter practice to consolidate taught ideas.
Original cumulative chapter practice to consolidate taught ideas. Solutions are available as revealable feedback and in a separate complete answer key. No answer submissions or accounts are required.
Assessment · 18 questions
Questions
Show your thinking; use diagrams when they help. Do not open solutions during your first attempt.
- A1
Compute 6 × 5. Explain a strategy using a known fact.
Reveal explanation
Answer: 30
6 groups of 5 make 6 × 5 = 30. Or find 5 × 5 and add 5.
6 rows of 5 dots = 30 dots. - A2
Compute 7 × 7. Explain a strategy using a known fact.
Reveal explanation
Answer: 49
7 groups of 7 make 7 × 7 = 49. Or find 6 × 7 and add 7.
7 rows of 7 dots = 49 dots. - A3
Use two useful multiplication facts to work out 7 × 6. What is the product?
Reveal explanation
Answer: 42
7 groups of 6 make 7 × 6 = 42. Or find 6 × 6 and add 6.
7 rows of 6 dots = 42 dots. - A4
Each tray holds 6 counters. How many full trays are required to arrange 48 counters?
Reveal explanation
Answer: 8
Find how many groups of 6 fit into 48: 48 ÷ 6 = 8.
6 rows of 8 dots = 48 dots. - A5
Compute 8 × 5. Explain a strategy using a known fact.
Reveal explanation
Answer: 40
8 groups of 5 make 8 × 5 = 40. Or find 7 × 5 and add 5.
8 rows of 5 dots = 40 dots. - A6
Compute 9 × 4. Explain a strategy using a known fact.
Reveal explanation
Answer: 36
9 groups of 4 make 9 × 4 = 36. Or find 8 × 4 and add 4.
9 rows of 4 dots = 36 dots. - A7
Use two useful multiplication facts to work out 8 × 7. What is the product?
Reveal explanation
Answer: 56
8 groups of 7 make 8 × 7 = 56. Or find 7 × 7 and add 7.
8 rows of 7 dots = 56 dots. - A8
Each tray holds 8 counters. How many full trays are required to arrange 48 counters?
Reveal explanation
Answer: 6
Find how many groups of 8 fit into 48: 48 ÷ 8 = 6.
8 rows of 6 dots = 48 dots. - A9
Find 6 groups of 3. Can you use 5 groups plus one more?
Reveal explanation
Answer: 18
6 groups of 3 make 6 × 3 = 18. Or find 5 × 3 and add 3.
6 rows of 3 dots = 18 dots. - A10
Find 7 groups of 10. Can you use 6 groups plus one more?
Reveal explanation
Answer: 70
7 groups of 10 make 7 × 10 = 70. Or find 6 × 10 and add 10.
7 rows of 10 dots = 70 dots. - A11
Explain how splitting 6 equal groups of 5 helps you find their total.
Reveal explanation
Answer: 30
6 groups of 5 make 6 × 5 = 30. Or find 5 × 5 and add 5.
6 rows of 5 dots = 30 dots. - A12
30 counters are shared equally into 6 groups. How many counters are in each group?
Reveal explanation
Answer: 5
Use inverse multiplication: 6 × 5 = 30; therefore 30 ÷ 6 = 5.
6 rows of 5 dots = 30 dots. - A13
Find 8 groups of 3. Can you use 7 groups plus one more?
Reveal explanation
Answer: 24
8 groups of 3 make 8 × 3 = 24. Or find 7 × 3 and add 3.
8 rows of 3 dots = 24 dots. - A14
Find 9 groups of 3. Can you use 8 groups plus one more?
Reveal explanation
Answer: 27
9 groups of 3 make 9 × 3 = 27. Or find 8 × 3 and add 3.
9 rows of 3 dots = 27 dots. - A15
Explain how splitting 9 equal groups of 3 helps you find their total.
Reveal explanation
Answer: 27
9 groups of 3 make 9 × 3 = 27. Or find 8 × 3 and add 3.
9 rows of 3 dots = 27 dots. - A16
27 stickers are arranged in complete groups of 8. How many complete groups and how many stickers remain?
Reveal explanation
Answer: 3 groups, 3 left
8 × 3 = 24, leaving 3. The remainder is smaller than 8.
- A17
An array has 7 rows of 4 dots. A student says turning it creates 4 more dots. Explain the error and find the total.
Reveal explanation
Answer: 28
Turning an array swaps rows and columns but adds no dots. Both 7 × 4 and 4 × 7 equal 28.
- A18
Without counting individual counters, show two different decompositions for 6 × 6, and explain why both work.
Reveal explanation
Answer: 36
One decomposition is (5 × 6) + (1 × 6) = 36. Another is (3 × 6) + (3 × 6) = 36. The partitions use different group splits but preserve the same product.