Regrouping Rescue Reference Sheet
Grade 3 Math Place Value Subtraction Helper
Regrouping Rescue: 3-Digit Algorithm & "Knock Next Door!"
🎶 THE BORROWING RHYME
More on top? No need to stop!
More on floor? Go next door!
The Story Metaphor How Regrouping Works: "Knock on the Neighbor's Door"
Always trade 1 for 10!
1. Check 3 < 7!
ONES "3 − 7? Not enough!"
Top ones digit is smaller! Must go next door!
2. Knock Next Door
TENS KNOCK! KNOCK! "Can I borrow a ten?"
Walk to Tens and knock on the door!
3. Share Tens − 1
"Take 1 Ten! I have 1 less now."
Tens gives 1 rod! 4 becomes 3.
4. Unpack +10 Ones!
"Walk back with 10! Now 3+10=13!"
Walk back with 10: 3 + 10 = 13! Now subtract!
A
3-Digit: Borrowing from the Tens
When the Ones digit is too small
e.g. 543 − 217
HUND (H) TENS (T) ONES (O)
+10
Regroup: —
3
13
5 4 / 3 /
− 2 1 7
3 2 6
1
ONES: 3 < 7! Knock on Tens! Slash 4 tens to make 3. Take 10 ones back: 3 + 10 = 13. Now: 13 − 7 = 6.
2
TENS: Subtract what's left in the tens: 3 − 1 = 2.
3
HUNDREDS: Subtract the hundreds column: 5 − 2 = 3. (Answer: 326!)
B
3-Digit: Borrowing from Hundreds
When the Tens digit is too small
e.g. 628 − 275
HUND (H) TENS (T) ONES (O)
+10
Regroup:
5
12
—
6 / 2 / 8
− 2 7 5
3 5 3
1
ONES: Check ones first: 8 ≥ 5! No need to borrow here! 8 − 5 = 3.
2
TENS: 2 < 7! Knock on Hundreds! Slash 6 hundreds to make 5. Bring 10 tens: 2 + 10 = 12. 12 − 7 = 5.
3
HUNDREDS: Subtract what's left in hundreds: 5 − 2 = 3. (Answer: 353!)
What if ZERO is next door in a 3-digit problem? Zero has no tens to give! Knock two doors down to the Hundreds (5 becomes 4). The 0 becomes 10 tens, then borrow 1 ten (10 becomes 9) for your ones!
3-Digit Algorithm Rules:
1. Start at 1s Always subtract right to left!
2. Slash & Write Neighbor − 1, your column + 10
3. Subtract Work through 1s, 10s, then 100s
Subtraction Solving Checklist
Subtraction Solving Checklist
3-Digit Regrouping Routine • Check Off Each Step As You Solve!
Name:
Date:
Say It Out Loud:
1. Where do we start? 👉 Always in the Ones place!
2. Can we subtract? 🤔 Is there enough? More on floor?
3. Where do we go now? 🚪 Knock next door! (Slash neighbor − 1)
4. Where do I bring tens? 🎒 Back to Ones! (+10 & subtract)
1 Problem 1: Borrowing for Ones 3-Digit Subtraction
H T O
5 4 2
− 1 2 8
My Solving Routine: Check off:
1. Start at Ones: Can we do 2 − 8?
(Circle: YES / NO)
2. Knock Next Door: Knock on Tens! Slash 4, write 3.
3. Bring Back 10: 2 + 10 = 12 in ones home!
4. Subtract All: 12 − 8 = ___, 3 − 2 = ___, 5 − 1 = ___.
2 Problem 2: Borrowing for Tens 3-Digit Subtraction
H T O
6 3 7
− 2 8 4
My Solving Routine: Check off:
1. Start at Ones: Can we do 7 − 4?
(Yes! 7 − 4 = 3)
2. Check Tens: Can we do 3 − 8? No!
3. Knock on Hundreds: Slash 6, write 5!
4. Bring 10 to Tens: 3 + 10 = 13! Subtract: 13 − 8 & 5 − 2!
3 Problem 3: Double Regrouping! Knock Twice!
H T O
7 2 4
− 3 6 8
My Solving Routine: Check off:
1. Ones: 4 < 8. Knock on Tens! Slash 2 to make 1. Ones becomes 14. 14 − 8 = ___.
2. Tens: Now 1 < 6! Can't subtract 6 from 1!
3. Knock Hundreds: Slash 7 to make 6. Tens becomes 1 + 10 = 11!
4. Finish Subtracting: 11 − 6 = ___, then 6 − 3 = ___!
4 Problem 4: Zero Next Door! Detective Challenge
H T O
5 0 3
− 2 4 7
My Solving Routine: Check off:
1. Ones: 3 < 7. Knock on Tens... but Tens is 0!
2. Go Two Doors Down: Knock on Hundreds! Slash 5 to make 4.
3. Tens Becomes 9: 0 becomes 10 tens, then lends 1 to ones (10 becomes ).
