3B · Chapter 8 · review
Chapter review
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 · 26 questions
Questions
Show your thinking; use diagrams when they help. Do not open solutions during your first attempt.
- A1
There are 6 equal trays with 7 counters on each tray. How many counters are there?
Reveal explanation
Answer: 42
6 groups of 7 make 6 × 7 = 42. Or find 5 × 7 and add 7.
6 rows of 7 dots = 42 dots. - A2
Compute 7 × 10. Explain a strategy using a known fact.
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. - A3
An array has 6 rows, with 10 objects in each row. Split it into smaller arrays and find the total.
Reveal explanation
Answer: 60
6 groups of 10 make 6 × 10 = 60. Or find 5 × 10 and add 10.
6 rows of 10 dots = 60 dots. - A4
24 counters are shared equally into 6 groups. How many counters are in each group?
Reveal explanation
Answer: 4
Use inverse multiplication: 6 × 4 = 24; therefore 24 ÷ 6 = 4.
6 rows of 4 dots = 24 dots. - A5
There are 8 equal trays with 8 counters on each tray. How many counters are there?
Reveal explanation
Answer: 64
8 groups of 8 make 8 × 8 = 64. Or find 7 × 8 and add 8.
8 rows of 8 dots = 64 dots. - A6
There are 9 equal trays with 7 counters on each tray. How many counters are there?
Reveal explanation
Answer: 63
9 groups of 7 make 9 × 7 = 63. Or find 8 × 7 and add 7.
9 rows of 7 dots = 63 dots. - A7
An array has 9 rows, with 9 objects in each row. Split it into smaller arrays and find the total.
Reveal explanation
Answer: 81
9 groups of 9 make 9 × 9 = 81. Or find 8 × 9 and add 9.
9 rows of 9 dots = 81 dots. - A8
64 counters are shared equally into 8 groups. How many counters are in each group?
Reveal explanation
Answer: 8
Use inverse multiplication: 8 × 8 = 64; therefore 64 ÷ 8 = 8.
8 rows of 8 dots = 64 dots. - A9
Compute 6 × 6. Explain a strategy using a known fact.
Reveal explanation
Answer: 36
6 groups of 6 make 6 × 6 = 36. Or find 5 × 6 and add 6.
6 rows of 6 dots = 36 dots. - A10
Find 7 groups of 5. Can you use 6 groups plus one more?
Reveal explanation
Answer: 35
7 groups of 5 make 7 × 5 = 35. Or find 6 × 5 and add 5.
7 rows of 5 dots = 35 dots. - A11
Explain how splitting 6 equal groups of 4 helps you find their total.
Reveal explanation
Answer: 24
6 groups of 4 make 6 × 4 = 24. Or find 5 × 4 and add 4.
6 rows of 4 dots = 24 dots. - A12
Each tray holds 6 counters. How many full trays are required to arrange 54 counters?
Reveal explanation
Answer: 9
Find how many groups of 6 fit into 54: 54 ÷ 6 = 9.
6 rows of 9 dots = 54 dots. - A13
Compute 8 × 7. Explain a strategy using a known fact.
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. - A14
Compute 9 × 10. Explain a strategy using a known fact.
Reveal explanation
Answer: 90
9 groups of 10 make 9 × 10 = 90. Or find 8 × 10 and add 10.
9 rows of 10 dots = 90 dots. - A15
Use two useful multiplication facts to work out 9 × 8. What is the product?
Reveal explanation
Answer: 72
9 groups of 8 make 9 × 8 = 72. Or find 8 × 8 and add 8.
9 rows of 8 dots = 72 dots. - A16
98 stickers are arranged in complete groups of 9. How many complete groups and how many stickers remain?
Reveal explanation
Answer: 10 groups, 8 left
9 × 10 = 90, leaving 8. The remainder is smaller than 9.
- A17
Find 6 groups of 7. Can you use 5 groups plus one more?
Reveal explanation
Answer: 42
6 groups of 7 make 6 × 7 = 42. Or find 5 × 7 and add 7.
6 rows of 7 dots = 42 dots. - A18
Compute 7 × 6. Explain a strategy using a known fact.
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. - A19
An array has 7 rows, with 4 objects in each row. Split it into smaller arrays and find the total.
Reveal explanation
Answer: 28
7 groups of 4 make 7 × 4 = 28. Or find 6 × 4 and add 4.
7 rows of 4 dots = 28 dots. - A20
60 counters are shared equally into 6 groups. How many counters are in each group?
Reveal explanation
Answer: 10
Use inverse multiplication: 6 × 10 = 60; therefore 60 ÷ 6 = 10.
6 rows of 10 dots = 60 dots. - A21
There are 8 equal trays with 7 counters on each tray. How many counters are there?
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. - A22
Find 9 groups of 5. Can you use 8 groups plus one more?
Reveal explanation
Answer: 45
9 groups of 5 make 9 × 5 = 45. Or find 8 × 5 and add 5.
9 rows of 5 dots = 45 dots. - A23
Explain how splitting 9 equal groups of 5 helps you find their total.
Reveal explanation
Answer: 45
9 groups of 5 make 9 × 5 = 45. Or find 8 × 5 and add 5.
9 rows of 5 dots = 45 dots. - A24
Each tray holds 9 counters. How many full trays are required to arrange 36 counters?
Reveal explanation
Answer: 4
Find how many groups of 9 fit into 36: 36 ÷ 9 = 4.
9 rows of 4 dots = 36 dots. - A25
An array has 7 rows of 5 dots. A student says turning it creates 5 more dots. Explain the error and find the total.
Reveal explanation
Answer: 35
Turning an array swaps rows and columns but adds no dots. Both 7 × 5 and 5 × 7 equal 35.
- A26
Without counting individual counters, show two different decompositions for 6 × 7, and explain why both work.
Reveal explanation
Answer: 42
One decomposition is (5 × 7) + (1 × 7) = 42. Another is (3 × 7) + (3 × 7) = 42. The partitions use different group splits but preserve the same product.