Triple Digit Challenge Worksheet
Math Mastery Grade 2–4
Triple Digit Challenge
Adding and Subtracting Three-Digit Numbers with Precision
Name:
Date: Score:
Directions: Work carefully from ones to hundreds. Show all carries and trades in the designated workspaces. Page 1 of 2
A
Warm-Up Zone: Foundational Computation (No Regrouping)
Align columns accurately
#1 Add
HTO
3 4 2
#2 Add
HTO
5 1 6
#3 Sub
HTO
8 7 5
− 3 4 1
#4 Sub
HTO
6 9 4
− 2 6 0
B
Regrouping Studio: Carrying & Borrowing Across Places
Record carried / borrowed digits in top boxes
#5 Regroup Ones
4 6 8
#6 Regroup Tens
3 7 4
#7 Double Regroup
5 8 7
#8 Trade 1 Ten
6 5 2
− 3 2 7
#9 Trade 1 Hundred
7 3 8
− 4 8 2
#10 Across Zero
6 0 4
− 2 7 8
Self-Check: Checked ones column first Wrote regrouped values Double-checked inverse operation
Continue to Page 2 →
Triple Digit Challenge • Part 2: Applications & Mixed Review
Name: Page 2 of 2
C
Word Problem Expedition: Real-World Applications
Write an equation, show vertical work, and include units
#11 Community Book Drive
The city library received a donation of 385 children’s storybooks in the morning and 278 science books in the afternoon. How many books did the library receive in all?
Equation:
Vertical Workspace
Answer:
books
#12 Canned Food Drive
Summit Elementary collected 740 canned goods for the winter pantry. Lincoln Elementary collected 485 cans. How many more cans did Summit Elementary collect than Lincoln Elementary?
Equation:
Vertical Workspace
Answer:
more cans
#13 Botanical Garden Seeds (Two-Step Challenge)
The school greenhouse had a pack of 820 flower seeds. On Monday, students planted 345 seeds. On Tuesday, they planted another 268 seeds. How many seeds are left in the pack?
Plan: Step 1: Total planted | Step 2: Seeds remaining
Work Area (Both Steps)
Answer:
seeds left
D
Mastery Analysis: Estimation & Glitch Buster
Reasoning & critical thinking
#14 Round to Nearest 100
Marcus estimates that \( 586 + 219 \) is about 900. Is his estimate reasonable?
586 rounds to:
219 rounds to:
Estimated Sum:
Marcus is:
Correct Incorrect
#15 Glitch Buster
A classmate solved this problem with a mistake. Find the glitch, explain it, and solve correctly!
Glitch Work:
5 2 3
− 2 8 1
3 6 2
What went wrong?
Correct Answer:
Awesome effort! Turn in your sheet for review and feedback.
Final Score: / 15
Triple Digit Challenge Answer Key
Teacher Guide Answer Key & Worked Solutions
Triple Digit Challenge — Key
Full step-by-step regrouping traces & diagnostic scoring notes
Total Points: 15 Points
Page 1: 10 pts (1 pt each)
Page 2: 5 pts (Word & analysis)
Scoring Rubric: Award full credit for correct regrouping marks even if minor arithmetic slips occur. Page 1 of 2
A
Warm-Up Zone: Solutions (No Regrouping)
1 pt each • Verify column alignment
#1 Answer: 496
HTO
3 4 2
4 9 6
#2 Answer: 789
HTO
5 1 6
7 8 9
#3 Answer: 534
HTO
8 7 5
− 3 4 1
5 3 4
#4 Answer: 434
HTO
6 9 4
− 2 6 0
4 3 4
B
Regrouping Studio: Solutions & Step Marks
Red marks show regrouped digits
#5 Ans: 683
1
4 6 8
6 8 3
Check: \(8 + 5 = 13\); write 3, carry 1 to tens. \(1 + 6 + 1 = 8\).
#6 Ans: 657
1
3 7 4
6 5 7
Check: \(7 + 8 = 15\); write 5, carry 1 to hundreds. \(1 + 3 + 2 = 6\).
#7 Ans: 856
1
1
5 8 7
8 5 6
Check: Double carry: \(7+9=16\) (carry 1); \(1+8+6=15\) (carry 1).
#8 Ans: 325
4
12
6 5 2
− 3 2 7
3 2 5
Check: Trade 1 ten for 10 ones: \(12 - 7 = 5\); \(4 - 2 = 2\); \(6 - 3 = 3\).
#9 Ans: 256
6
13
7 3 8
− 4 8 2
2 5 6
Check: Trade 1 hundred: \(13 - 8 = 5\) tens; \(6 - 4 = 2\) hundreds.
#10 Ans: 326
5
9
14
6 0 4
− 2 7 8
3 2 6
Check: Across zero: 6 hundreds becomes 5; tens become 10 then 9; ones 14.