Grade 4 Answer Key • Operations Mastery Page 1 of 2 • Continue to Multiplication Key →
Teacher Reference Part 2 Answer Key
Standards: CCSS.MATH.CONTENT.4.NBT.B.5
D
1 pt each
Problem 11 3,402
486 × 7
• 7 × 6 = 42
• 7 × 80 = 560
• 7 × 400 = 2,800
Sum = 3,402
Problem 12 14,070
2,345 × 6
• 6 × 5 = 30
• 6 × 40 = 240
• 6 × 300 = 1,800
• 6 × 2,000 = 12,000
Sum = 14,070
Problem 13 912
38 × 24
• 38 × 4 = 152
• 38 × 20 = 760
152 + 760 = 912
Problem 14 2,052
57 × 36
• 57 × 6 = 342
• 57 × 30 = 1,710
342 + 1,710 = 2,052
Problem 15 4,018
82 × 49
• 82 × 9 = 738
• 82 × 40 = 3,280
738 + 3,280 = 4,018
Problem 16 4,800
64 × 75 (Challenge)
• 64 × 5 = 320
• 64 × 70 = 4,480
320 + 4,480 = 4,800
E
1 pt
17. District Book Shipment Solution Answer: 130 spare workbooks
Total Books Delivered:
35 boxes × 28 books/box
= 35 × (20 + 8)
= 700 + 280 = 980 books
Remaining After Distribution:
980 total books − 850 students
= 130 spare workbooks
F
1 pt
Identified Error:
Maya forgot the place value of the tens digit. In 32, the digit 3 represents 30, not 3 ones. Therefore, she should have calculated 45 × 30 = 1,350, rather than 45 × 3 = 135. She omitted the essential placeholder zero in the second partial product.
Acceptable Explanations:
Correct Solution:
45
× 32
----
90 (45 × 2)
1350 (45 × 30)
----
1,440
Full credit requires both correct explanation and product: 1,440.
Grade 4 Answer Key • Operations Mastery Page 2 of 2 • Math Powerhouse
582
×43
13. 3-Digit × 2-Digit
714
×65
14. Zero in Tens Place
809
×54
15. 4-Digit × 2-Digit
1,425
×36
16. Advanced Challenge
2,860
×47
E
17. Transcontinental Fleet Capacity Multi-Tier Multiplication
Skyline Air operates 48 round-trip flights each week between New York and London. Each aircraft carries an average of 275 passengers per flight. During a 12-week peak summer travel season, how many total passengers are transported by this flight route?
Show Your Step-by-Step Multiplication:
Total Seasonal Passengers:
passengers
F
18. Uncover the Unknown Factor!
A researcher found an equation in an engineering logbook where the second multiplier was smudged:
325 × [ ? ] = 15,600
Explain your deduction strategy (estimation, benchmark numbers, or inverse ops):
Strategy Space:
Test your factor:
Missing Factor (?):
Grade 5 • Number & Operations in Base Ten Page 2 of 2 • Math Powerhouse
Grade 5 Answer Key • Operations Mastery Page 1 of 2 • Continue to Multiplication Key →
Teacher Reference Part 2 Answer Key
Standards: CCSS.MATH.CONTENT.5.NBT.B.5
D
1 pt each
Problem 11 9,688
346 × 28
• 346 × 8 = 2,768
• 346 × 20 = 6,920
2,768 + 6,920 = 9,688
Problem 12 25,026
582 × 43
• 582 × 3 = 1,746
• 582 × 40 = 23,280
1,746 + 23,280 = 25,026
Problem 13 46,410
714 × 65
• 714 × 5 = 3,570
• 714 × 60 = 42,840
3,570 + 42,840 = 46,410
Problem 14 43,686
809 × 54 (Zero in Tens)
• 809 × 4 = 3,236
• 809 × 50 = 40,450
3,236 + 40,450 = 43,686
Problem 15 51,300
1,425 × 36
• 1,425 × 6 = 8,550
• 1,425 × 30 = 42,750
8,550 + 42,750 = 51,300
Problem 16 134,420
2,860 × 47 (Challenge)
• 2,860 × 7 = 20,020
• 2,860 × 40 = 114,400
20,020 + 114,400 = 134,420
E
1 pt
17. Transcontinental Fleet Capacity Solution Answer: 158,400 passengers
Method 1 (Weekly → Season):
48 flights × 275 passengers = 13,200/wk
13,200 passengers × 12 weeks
= 158,400 passengers
Method 2 (Total Flights → Pass):
48 flights/wk × 12 weeks = 576 flights
576 flights × 275 passengers
= 158,400 passengers
F
1 pt
Target: 325 × [ ? ] = 15,600
Students may use either benchmark estimation or inverse division to determine the missing factor.
Strategy A (Decomposition/Estimation):
• Estimate using 325 × 40 = 13,000.
• Remaining value: 15,600 − 13,000 = 2,600.
• Determine how many 325s in 2,600: 325 × 8 = 2,600.
• Combine: 40 + 8 = 48.
Strategy B (Inverse Operation):
15,600 ÷ 325 = 48 (check: 48 × 325 = 15,600).
Correct Value:
? = 48
Accept any mathematically sound deduction strategy that demonstrates place-value reasoning.
Grade 5 Answer Key • Operations Mastery Page 2 of 2 • Math Powerhouse
