Three-digit addition practice worksheet with missing numbers and shaded answers.

Of course! Let's solve each of the 9 addition problems step by step. Each problem is set up in a place-value grid (Hundreds, Tens, Ones), and some digits are missing (shown as gray boxes). We need to fill in the missing digits so that the addition is correct.

We’ll go row by row, left to right.

---

Problem 1 (Top Left)

```
2 3 1
+ 4 2 5
= 6 5 6
```
✔ Already complete and correct:
- Ones: 1 + 5 = 6
- Tens: 3 + 2 = 5
- Hundreds: 2 + 4 = 6

No missing digits.

---

Problem 2 (Top Middle)

```
? 7 1
+ 1 2 ?
= 6 9 2
```
Let’s find the missing digits:

- Ones place: 1 + ? = 2 → ? = 1
- Tens place: 7 + 2 = 9 → ✔ correct
- Hundreds place: ? + 1 = 6 → ? = 5

✔ So, the top number is 571, bottom is 121, sum is 692

Missing digits: 5 (hundreds of top), 1 (ones of bottom)

---

Problem 3 (Top Right)

```
1 0 1
+ 4 ? 8
= ? 4 9
```
Find missing digits:

- Ones place: 1 + 8 = 9 → ✔ correct
- Tens place: 0 + ? = 4 → ? = 4
- Hundreds place: 1 + 4 = 5 → so sum’s hundreds digit is 5

✔ Top: 101, Bottom: 448, Sum: 549

Missing digits: 4 (tens of bottom), 5 (hundreds of sum)

---

Problem 4 (Middle Left)

```
2 4 ?
+ ? ? 3
= 6 6 4
```
Find missing digits:

- Ones place: ? + 3 = 4 → ? = 1
- Tens place: 4 + ? = 6 → ? = 2
- Hundreds place: 2 + ? = 6 → ? = 4

✔ Top: 241, Bottom: 423, Sum: 664

Missing digits: 1 (ones of top), 4 (hundreds of bottom), 2 (tens of bottom)

---

Problem 5 (Middle Center)

```
3 3 1
+ ? 4
= ? 5 5
```
Note: The bottom number has no hundreds digit — it’s a 2-digit number (so hundreds digit is 0).

- Ones place: 1 + 4 = 5 → ✔ correct
- Tens place: 3 + ? = 5 → ? = 2
- Hundreds place: 3 + 0 = 3 → so sum’s hundreds digit is 3

✔ Top: 331, Bottom: 24, Sum: 355

Missing digits: 2 (tens of bottom), 3 (hundreds of sum)

---

Problem 6 (Middle Right)

```
4 ? 1
+ ? 0 8
= 7 8 9
```
Find missing digits:

- Ones place: 1 + 8 = 9 → ✔ correct
- Tens place: ? + 0 = 8 → ? = 8
- Hundreds place: 4 + ? = 7 → ? = 3

✔ Top: 481, Bottom: 308, Sum: 789

Missing digits: 8 (tens of top), 3 (hundreds of bottom)

---

Problem 7 (Bottom Left)

```
6 7 1
+ ? ? 0
= 8 8 ?
```
Find missing digits:

- Ones place: 1 + 0 = 1 → so sum’s ones digit is 1
- Tens place: 7 + ? = 8 → ? = 1
- Hundreds place: 6 + ? = 8 → ? = 2

✔ Top: 671, Bottom: 210, Sum: 881

Missing digits: 2 (hundreds of bottom), 1 (tens of bottom), 1 (ones of sum)

---

Problem 8 (Bottom Middle)

```
? 2 1
+ 1 ? 8
= 2 4 ?
```
Find missing digits:

- Ones place: 1 + 8 = 9 → so sum’s ones digit is 9
- Tens place: 2 + ? = 4 → ? = 2
- Hundreds place: ? + 1 = 2 → ? = 1

✔ Top: 121, Bottom: 128, Sum: 249

Missing digits: 1 (hundreds of top), 2 (tens of bottom), 9 (ones of sum)

---

Problem 9 (Bottom Right)

```
7 5 1
+ ? ? ?
= 4 7 1
```
Wait — this looks odd. 751 + something = 471? That would mean adding a *negative* number. But since this is elementary math with only positive digits, let’s check for carrying errors or misreading.

Actually, 751 + X = 471 → X = 471 - 751 = -280 — impossible with positive digits.

But look again — maybe there’s a carryover we missed?

Let’s do column-by-column carefully:

- Ones: 1 + ? = 1 → ? = 0
- Tens: 5 + ? = 7 → ? = 2
- Hundreds: 7 + ? = 4 → Hmm... 7 + ? can’t be 4 unless we have a carry from tens? Wait — but 5 + 2 = 7, no carry.

This suggests an error — unless the sum is actually 1471? But the grid only shows 3 digits.

Wait — perhaps the sum is 1471, and the “4” in the hundreds place is actually the *tens of thousands*? No, the grid only has 3 columns.

Alternatively, maybe the top number is not 751? But it’s printed clearly.

Wait — let’s try subtraction: 471 - 751 = -280 — not possible.

Conclusion: This problem likely has a typo, OR we must consider that the sum is actually 1471, meaning there’s a thousands digit that’s not shown.

But the worksheet only has 3 columns: Hundreds, Tens, Ones.

So let’s assume the sum is 1471, and the "4" is in the *hundreds* place, meaning there’s a 1 carried over to thousands.

That makes sense!

So:

- Ones: 1 + ? = 1 → ? = 0
- Tens: 5 + ? = 7 → ? = 2
- Hundreds: 7 + ? = 14 (because we need to get 4 in hundreds and carry 1 to thousands) → ? = 7

Because 7 + 7 = 14 → write 4, carry 1 → which becomes the thousands digit.

✔ So: 751 + 720 = 1471

But the sum is written as “471” — missing the thousands digit.

Since the worksheet only shows 3 columns, perhaps the intended answer is to fill in the digits assuming the sum is 1471, and the "1" is implied or omitted.

In many worksheets, if there’s a carryover beyond the highest place value, they might just show the last 3 digits — but that’s misleading.

Given the context, the most logical solution is:

- Bottom number: 720
- Sum: 1471 (but written as 471 — possibly an error)

To match the grid, we'll fill in:

- Bottom: 7 (hundreds), 2 (tens), 0 (ones)
- Sum: 4 (hundreds), 7 (tens), 1 (ones) — and ignore the thousands digit for now.

✔ So missing digits: 7, 2, 0 (bottom), and the sum is already filled as 471 (though technically incomplete).

Missing digits: 7 (hundreds of bottom), 2 (tens of bottom), 0 (ones of bottom)

---

## ✔ Final Answers (Filling in the Gray Boxes):

Row 1:

- Problem 1: No missing digits.
- Problem 2: Top hundreds = 5, Bottom ones = 1
- Problem 3: Bottom tens = 4, Sum hundreds = 5

Row 2:

- Problem 4: Top ones = 1, Bottom hundreds = 4, Bottom tens = 2
- Problem 5: Bottom tens = 2, Sum hundreds = 3
- Problem 6: Top tens = 8, Bottom hundreds = 3

Row 3:

- Problem 7: Bottom hundreds = 2, Bottom tens = 1, Sum ones = 1
- Problem 8: Top hundreds = 1, Bottom tens = 2, Sum ones = 9
- Problem 9: Bottom hundreds = 7, Bottom tens = 2, Bottom ones = 0

---

## 📝 Summary of All Missing Digits (in order, left to right, top to bottom):

1. 5, 1
2. 4, 5
3. 1, 4, 2
4. 2, 3
5. 8, 3
6. 2, 1, 1
7. 1, 2, 9
8. 7, 2, 0

---

✔ You can now fill in all the gray boxes with these numbers!

Let me know if you’d like a visual version or printable answer key!