A focused practice set on three-digit subtraction with regrouping, incorporating base-ten block models, structured place value grids, zero-zone subtraction, and contextual word problems.
Remember: Trade 1 hundred for 10 tens first, then trade 1 ten for 10 ones!
7. 600 − 347
H
T
O
6
0
0
−
3
4
7
8. 703 − 428
H
T
O
7
0
3
−
4
2
8
9. 900 − 582
H
T
O
9
0
0
−
5
8
2
10. 501 − 264
H
T
O
5
0
1
−
2
6
4
4
Real-World Story Problems
11. Bakery Milestone: Oakwood Bakery baked 615 blueberry muffins for a morning charity run. Customers bought 389 muffins before noon. How many muffins are left?
Show Your Work / Place Value Grid:
Final Answer:
muffins
12. State Park Hike: A nature trail is 700 yards long. Julian has already hiked 458 yards. How many yards does Julian have left to reach the overlook?
Show Your Work / Place Value Grid:
Final Answer:
yards
5
Math Detective: Find the Regrouping Mistake
Alex's Work
7 0 5
− 3 4 8
4 4 3 ✗
What mistake did Alex make when subtracting across the zero, and what is the correct difference?
Alex subtracted bottom from top (8−5=3, 4−0=4, 7−3=4) rather than regrouping across the zero from the hundreds place.
Correct difference: 357
Regrouping Trail • Set 2 Key Page 2 of 2
7. 800 − 456
H
T
O
8
0
0
−
4
5
6
8. 905 − 368
H
T
O
9
0
5
−
3
6
8
9. 600 − 279
H
T
O
6
0
0
−
2
7
9
10. 704 − 389
H
T
O
7
0
4
−
3
8
9
4
Real-World Story Problems
11. Aquarium Visitors: On Saturday, 842 people entered the marine aquarium. 475 were children and the rest were adults. How many adults visited the aquarium?
Show Your Work / Place Value Grid:
Final Answer:
adults
12. Stadium Seating: Section B of the sports arena has 500 seats. For tonight's game, 327 tickets have been sold. How many empty seats remain in Section B?
Show Your Work / Place Value Grid:
Final Answer:
seats
5
Math Detective: Find the Regrouping Mistake
Jordan's Work
5 3 2
− 2 7 8
3 4 4 ✗
What mistake did Jordan make in the ones and tens places, and what is the correct difference?
Jordan subtracted upside down (8−2=4 or miscalculated 8−2, 7−3=4) instead of regrouping from tens and hundreds.
Correct difference: 254
Regrouping Summit • Set 3 Key Page 2 of 2
7. 400 − 187
H
T
O
4
0
0
−
1
8
7
8. 806 − 349
H
T
O
8
0
6
−
3
4
9
9. 500 − 263
H
T
O
5
0
0
−
2
6
3
10. 903 − 578
H
T
O
9
0
3
−
5
7
8
4
Real-World Story Problems
11. Ocean Cruise Cargo: A cargo vessel had 752 shipping crates on board. At the island port, dockworkers unloaded 487 crates. How many crates remained on the vessel?
Show Your Work / Place Value Grid:
Final Answer:
crates
12. Marina Boat Slips: Seaside Harbor has 600 total boat slips. On Monday morning, 374 boats left for open-sea fishing. How many boats are currently in their slips?
Show Your Work / Place Value Grid:
Final Answer:
boats
5
Math Detective: Find the Regrouping Mistake
Mia's Work
8 0 0
− 4 3 6
4 7 4 ✗
What mistake did Mia make with the hundreds place after regrouping, and what is the correct difference?
Mia forgot to reduce the hundreds place to 7 (she did 8−4=4), and in the tens place she didn't realize 10 tens was reduced to 9 tens.
Correct difference: 364
Regrouping Voyage • Set 4 Key Page 2 of 2
7. 700 − 364
H
T
O
7
0
0
−
3
6
4
8. 603 − 275
H
T
O
6
0
3
−
2
7
5
9. 900 − 438
H
T
O
9
0
0
−
4
3
8
10. 801 − 357
H
T
O
8
0
1
−
3
5
7
4
Real-World Story Problems
11. Robotics Build: The tech club received a box of 645 circuit components. They used 378 components to build competition rovers. How many spare components remain?
Show Your Work / Place Value Grid:
Final Answer:
components
12. Solar Power Cells: An eco-station has a battery capacity target of 500 kilowatt-hours. The solar panels have generated 284 kilowatt-hours. How many more kWh are needed?
Show Your Work / Place Value Grid:
Final Answer:
kWh
5
Math Detective: Find the Regrouping Mistake
Noah's Work
7 2 5
− 3 8 9
4 6 4 ✗
What mistake did Noah make in the tens and hundreds places, and what is the correct difference?
Noah subtracted upside down in the ones place (9−5=4) and tens place (8−2=6), rather than regrouping from the next higher place values.
Correct difference: 336
Regrouping Circuit • Set 5 Key Page 2 of 2
7. 500 − 247
H
T
O
5
0
0
−
2
4
7
8. 702 − 386
H
T
O
7
0
2
−
3
8
6
9. 800 − 453
H
T
O
8
0
0
−
4
5
3
10. 605 − 289
H
T
O
6
0
5
−
2
8
9
4
Real-World Story Problems
11. Wildlife Safari Park: A nature reserve tracked 736 migratory birds in the valley. By autumn, 489 birds flew south. How many birds remain in the valley?
Show Your Work / Place Value Grid:
Final Answer:
birds
12. Ranger Patrol Miles: Forest rangers set a monthly patrol target of 600 trail miles. They completed 347 miles in the first two weeks. How many miles remain?
Show Your Work / Place Value Grid:
Final Answer:
miles
5
Math Detective: Find the Regrouping Mistake
Ella's Work
6 1 4
− 2 8 7
4 7 3 ✗
What mistake did Ella make in her column subtractions, and what is the correct difference?
Ella subtracted upside down in the ones (7−4=3) and tens (8−1=7) places rather than regrouping from the next place value.
Correct difference: 327
Regrouping Safari • Set 6 Key Page 2 of 2
7. 600 − 258
H
T
O
6
0
0
−
2
5
8
8. 804 − 437
H
T
O
8
0
4
−
4
3
7
9. 700 − 384
H
T
O
7
0
0
−
3
8
4
10. 902 − 568
H
T
O
9
0
2
−
5
6
8
4
Real-World Story Problems
11. Mountain Trail Climb: An expedition route covers 814 meters of elevation. The climbers have reached 549 meters. How many meters remain to the summit ridge?
Show Your Work / Place Value Grid:
Final Answer:
meters
12. Base Camp Supplies: Base camp packed 700 energy bars. The team consumed 418 bars during the first week. How many energy bars are left?
Show Your Work / Place Value Grid:
Final Answer:
bars
5
Math Detective: Find the Regrouping Mistake
Zack's Work
7 0 0
− 3 5 4
4 5 6 ✗
What mistake did Zack make in the tens and hundreds places, and what is the correct difference?
Zack did not decrease the hundreds place to 6 (7−3=4) and treated the tens place as 10 rather than 9 after regrouping to the ones place.
Correct difference: 346
Regrouping Expedition • Set 7 Key Page 2 of 2
7. 800 − 372
H
T
O
8
0
0
−
3
7
2
8. 604 − 287
H
T
O
6
0
4
−
2
8
7
9. 500 − 186
H
T
O
5
0
0
−
1
8
6
10. 701 − 345
H
T
O
7
0
1
−
3
4
5
4
Real-World Story Problems
11. Basketball Tournament: The arena sold 825 tournament t-shirts. Fans purchased 478 shirts during the semifinal round. How many shirts are left for the finals?
Show Your Work / Place Value Grid:
Final Answer:
shirts
12. Track & Field Goal: A runner has a season goal of running 500 laps around the school track. She has finished 267 laps so far. How many laps remain?
Show Your Work / Place Value Grid:
Final Answer:
laps
5
Math Detective: Find the Regrouping Mistake
Tyler's Work
7 3 1
− 3 8 4
4 5 3 ✗
What mistake did Tyler make in his ones and tens places, and what is the correct difference?
Tyler subtracted bottom from top (4−1=3, 8−3=5, 7−3=4) rather than regrouping from the tens and hundreds places.
Correct difference: 347
Regrouping Arena • Set 8 Key Page 2 of 2
7. 900 − 458
H
T
O
9
0
0
−
4
5
8
8. 706 − 349
H
T
O
7
0
6
−
3
4
9
9. 600 − 273
H
T
O
6
0
0
−
2
7
3
10. 802 − 475
H
T
O
8
0
2
−
4
7
5
4
Real-World Story Problems
11. Planetarium Field Trip: The science museum welcomed 753 students for space week shows. 489 attended the morning sessions. How many attended the afternoon shows?
Show Your Work / Place Value Grid:
Final Answer:
students
12. Rocket Fuel Reserves: A mission tank has a max capacity of 600 liters of test propellent. The countdown consumed 365 liters. How many liters remain?
Show Your Work / Place Value Grid:
Final Answer:
liters
5
Math Detective: Find the Regrouping Mistake
Ava's Work
8 0 5
− 4 3 8
4 7 3 ✗
What mistake did Ava make in the ones and hundreds places, and what is the correct difference?
Correct difference:
Regrouping Orbit • Set 9 Page 2 of 2
13
5
7
3
−
2
8
9
2
8
4
6. 412 − 165
H
T
O
3
10
12
4
1
2
−
1
6
5
2
4
7
Regrouping Orbit • Set 9 Key Page 1 of 2 ➔
Answer Key • Set 9 Part 2
Fully Worked Solutions
3
The Zero Zone: Across Zeros (Solutions)
Check Regrouping
7. 900 − 458
H
T
O
8
9
10
9
0
0
−
4
5
8
4
4
2
8. 706 − 349
H
T
O
6
9
16
7
0
6
−
3
4
9
3
5
7
9. 600 − 273
H
T
O
5
9
10
6
0
0
−
2
7
3
3
2
7
10. 802 − 475
H
T
O
7
9
12
8
0
2
−
4
7
5
3
2
7
4
Real-World Story Problems (Worked Solutions)
11. Planetarium Field Trip: 753 students − 489 morning.
Ava subtracted upside down in the ones place (8−5=3) and forgot to reduce the hundreds place to 7 after regrouping.
Correct difference: 367
Regrouping Orbit • Set 9 Key Page 2 of 2
7. 700 − 348
H
T
O
7
0
0
−
3
4
8
8. 805 − 367
H
T
O
8
0
5
−
3
6
7
9. 600 − 184
H
T
O
6
0
0
−
1
8
4
10. 904 − 478
H
T
O
9
0
4
−
4
7
8
4
Real-World Story Problems
11. Grand Concert Tickets: The civic symphony printed 852 tickets for the annual gala. By opening night, music fans had bought 489 tickets. How many tickets remain available at the box office?
Show Your Work / Place Value Grid:
Final Answer:
tickets
12. Science Fair Score Goal: A student engineering team set a total project goal of 700 evaluation points. Their prototype phase scored 354 points. How many points are needed in the final presentation?
Show Your Work / Place Value Grid:
Final Answer:
points
5
Math Detective: Find the Regrouping Mistake
Ben's Work
8 0 0
− 3 6 5
5 4 5 ✗
What mistake did Ben make when subtracting across the zeros, and what is the correct difference?
Correct difference:
Regrouping Matrix • Set 10 Mastery Page 2 of 2
15
13
5
6
3
−
2
9
5
2
6
8
6. 426 − 189
H
T
O
3
11
16
4
2
6
−
1
8
9
2
3
7
Regrouping Matrix • Set 10 Key Page 1 of 2 ➔
Answer Key • Set 10 Part 2
Fully Worked Solutions
3
The Zero Zone: Across Zeros (Solutions)
Check Regrouping
7. 700 − 348
H
T
O
6
9
10
7
0
0
−
3
4
8
3
5
2
8. 805 − 367
H
T
O
7
9
15
8
0
5
−
3
6
7
4
3
8
9. 600 − 184
H
T
O
5
9
10
6
0
0
−
1
8
4
4
1
6
10. 904 − 478
H
T
O
8
9
14
9
0
4
−
4
7
8
4
2
6
4
Real-World Story Problems (Worked Solutions)
11. Grand Concert Tickets: 852 tickets − 489 sold.
