Unbundling Subtraction Practice Packet
3
Unbundling Subtraction
Week of Math Mastery • 3-Digit Regrouping
Name:
Date:
Monday Skill Focus: What Does It Mean to Unbundle?
"More on the floor? Go next door and take 10 more!"
The Rule of Ten: Trading Value Between Columns
1T
Unbundling a Ten
When you don't have enough Ones, unbundle 1 Ten rod into 10 Unit cubes.
1 Ten = 10 Ones
1H
Unbundling a Hundred
When you don't have enough Tens, unbundle 1 Hundred flat into 10 Ten rods.
1 Hundred = 10 Tens
Worked Example: Watch How We Unbundle \(452 - 128\)
1
Look at the Ones: \(2 - 8\)? Not enough! We need more ones.
2
Unbundle 1 Ten: Cross out 5 tens \(\rightarrow\) write 4. Add 10 to the ones: \(2 + 10 =\) 12.
3
Subtract Ones: \(12 - 8 = \mathbf{4}\).
4
Subtract Tens: \(4 - 2 = \mathbf{2}\). Subtract Hundreds: \(4 - 1 = \mathbf{3}\).
H T O
- 4 12
4 5 2
− 1 2 8
3 2 4
Guided Practice: Cross Out & Unbundle!
Fill in the top boxes with your new regrouped numbers.
Problem 1 Unbundle 1 Ten
H T O
3 6 4
− 1 2 7
Problem 2 Unbundle 1 Ten
H T O
5 8 3
− 2 4 6
Problem 3 Unbundle 1 Ten
H T O
7 4 1
− 3 1 8
Self Check Did you start subtracting at the Ones column on the right?
Yes Need Help
Tuesday
Practice Round 1: Unbundling Tens
Name:
Score: / 8
Coach Tip: Always check: Is top digit < bottom digit in the ones place? If yes, take 1 ten and give 10 to the ones!
Part A: Fluency Practice • Cross Out and Write New Numbers Above
- 542 − 215
HTO
542
−215
- 673 − 348
HTO
673
−348
- 481 − 156
HTO
481
−156
- 894 − 439
HTO
894
−439
- 765 − 227
HTO
765
−227
- 952 − 624
HTO
952
−624
! Part B: Detective Math • Spot & Fix the Mistake!
Careless Carl solved this problem. What did he do wrong?
Carl's Paper
4 6 2
− 1 3 8
3 3 6
"I did 8 − 2 = 6 in the ones place!"
Explain Carl's mistake:
Correct Solution
462
−138
3rd Grade Mathematics • Place Value Subtraction Day 2 of 4
Wednesday
Practice Round 2: Unbundling Hundreds
Name:
Score: / 8
H→T
What if the Tens digit is smaller?
Go to the Hundreds column! Unbundle 1 Hundred into 10 Tens. Add 10 to your tens digit.
Part A: Unbundle the Hundreds Digit • Cross Out and Regroup
- 627 − 284
HTO
627
−284
- 519 − 173
HTO
519
−173
- 836 − 472
HTO
836
−472
- 748 − 385
HTO
748
−385
- 925 − 461
HTO
925
−461
- 416 − 152
HTO
416
−152
★ Part B: Master Challenge • Double Unbundling! (Regroup Twice)
Unbundle ones first, then unbundle tens!
Challenge 1 632 − 275
Hint: You will need to borrow for both Ones and Tens!
HTO
632
−275
Challenge 2 524 − 186
Hint: Take your time crossing out and rewriting.
HTO
524
−186
3rd Grade Mathematics • Place Value Subtraction Day 3 of 4
Thu & Fri
Word Problems of the Week
Name:
Score: / 4
Problem Solving Steps: 1. Circle the numbers | 2. Underline the question | 3. Set up vertical subtraction | 4. Check if you need to unbundle!
1 The School Book Drive
Oakridge Elementary collected 435 books during their annual reading fair. On Friday, the student council donated 178 books to the children's hospital library. How many books does the school have left?
Answer: The school has books left.
Work Space
435
−178
2 The Apple Orchard Harvest
Farmer Maya picked 652 crisp apples on Saturday morning. By the end of the afternoon farmers market, she had sold 287 apples. How many apples does Farmer Maya still have left to sell?
Answer: Farmer Maya has apples left.
Work Space
652
−287
3 The Video Game High Score
Leo accumulated 814 total points playing Cosmic Blaster. His friend Marcus scored 459 points. How many more points did Leo score than Marcus?
Answer: Leo scored more points.
Work Space
814
−459
4 The Mountain Nature Trail
The Pine Peak nature trail is 741 meters long from start to finish. Sofia and her family have already walked 368 meters. How many more meters do they need to walk to reach the trail end?
Answer: They have meters left to walk.
Work Space
741
−368
Weekly Mission Complete! How confident do you feel with unbundling 3-digit subtraction?
⭐ Growing ⭐⭐ Strong ⭐⭐⭐ Expert
