Adding 4-Digit Numbers (Year 4) | CGP Plus - Free Printable

Let's solve each addition problem step by step, following the method shown in the example: first estimate by rounding to the nearest 100, then solve the exact addition, and finally check if the answer is close to the estimate.

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🔹 Problem 1 (Already Solved as Example)

- Estimate:
$ 5300 + 3500 = 8800 $

- Exact Addition:
$ 5321 + 3487 = 8808 $

✔ Check: 8808 is very close to 8800 → ✔️ Good estimate!

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🔹 Problem 2

#### Numbers:
- $ 7129 + 2241 $

#### Step 1: Estimate
Round both numbers to the nearest 100:
- $ 7129 \approx 7100 $
- $ 2241 \approx 2200 $
- Estimate: $ 7100 + 2200 = 9300 $

#### Step 2: Exact Addition

Use column method:

```
Th H T O
7 1 2 9
+ 2 2 4 1
-----------------
9 3 7 0
```

Carry-over:
- Ones: $ 9 + 1 = 10 $ → write 0, carry 1
- Tens: $ 2 + 4 + 1 = 7 $
- Hundreds: $ 1 + 2 = 3 $
- Thousands: $ 7 + 2 = 9 $

So, $ 7129 + 2241 = 9370 $

✔ Check: Estimate was 9300, actual is 9370 → very close! ✔️

> Answer:
> - Estimate: $ 7100 + 2200 = 9300 $
> - Exact: $ 7129 + 2241 = 9370 $

---

🔹 Problem 3

#### Numbers:
- $ 4217 + 1854 $

#### Step 1: Estimate
Round to nearest 100:
- $ 4217 \approx 4200 $
- $ 1854 \approx 1900 $
- Estimate: $ 4200 + 1900 = 6100 $

#### Step 2: Exact Addition

```
Th H T O
4 2 1 7
+ 1 8 5 4
-----------------
6 0 7 1
```

Carry-over:
- Ones: $ 7 + 4 = 11 $ → write 1, carry 1
- Tens: $ 1 + 5 + 1 = 7 $
- Hundreds: $ 2 + 8 = 10 $ → write 0, carry 1
- Thousands: $ 4 + 1 + 1 = 6 $

So, $ 4217 + 1854 = 6071 $

✔ Check: Estimate was 6100, actual is 6071 → very close! ✔️

> Answer:
> - Estimate: $ 4200 + 1900 = 6100 $
> - Exact: $ 4217 + 1854 = 6071 $

---

🔹 Problem 4

#### Numbers:
- $ 3248 + 4821 $

#### Step 1: Estimate
Round to nearest 100:
- $ 3248 \approx 3200 $
- $ 4821 \approx 4800 $
- Estimate: $ 3200 + 4800 = 8000 $

#### Step 2: Exact Addition

```
Th H T O
3 2 4 8
+ 4 8 2 1
-----------------
8 0 6 9
```

Carry-over:
- Ones: $ 8 + 1 = 9 $
- Tens: $ 4 + 2 = 6 $
- Hundreds: $ 2 + 8 = 10 $ → write 0, carry 1
- Thousands: $ 3 + 4 + 1 = 8 $

So, $ 3248 + 4821 = 8069 $

✔ Check: Estimate was 8000, actual is 8069 → very close! ✔️

> Answer:
> - Estimate: $ 3200 + 4800 = 8000 $
> - Exact: $ 3248 + 4821 = 8069 $

---

🔹 Problem 5

#### Numbers:
- $ 8746 + 714 $

Note: 714 is a 3-digit number, but we can still add it.

#### Step 1: Estimate
Round to nearest 100:
- $ 8746 \approx 8700 $
- $ 714 \approx 700 $
- Estimate: $ 8700 + 700 = 9400 $

#### Step 2: Exact Addition

Write 714 as 0714 for alignment:

```
Th H T O
8 7 4 6
+ 0 7 1 4
-----------------
9 4 5 0
```

Carry-over:
- Ones: $ 6 + 4 = 10 $ → write 0, carry 1
- Tens: $ 4 + 1 + 1 = 6 $
- Hundreds: $ 7 + 7 = 14 $ → write 4, carry 1
- Thousands: $ 8 + 0 + 1 = 9 $

So, $ 8746 + 714 = 9460 $

✔ Check: Estimate was 9400, actual is 9460 → very close! ✔️

> Answer:
> - Estimate: $ 8700 + 700 = 9400 $
> - Exact: $ 8746 + 714 = 9460 $

---

✔ Final Answers Summary:

| Problem | Estimate | Exact Answer |
|--------|----------|--------------|
| 1 | 5300 + 3500 = 8800 | 5321 + 3487 = 8808 |
| 2 | 7100 + 2200 = 9300 | 7129 + 2241 = 9370 |
| 3 | 4200 + 1900 = 6100 | 4217 + 1854 = 6071 |
| 4 | 3200 + 4800 = 8000 | 3248 + 4821 = 8069 |
| 5 | 8700 + 700 = 9400 | 8746 + 714 = 9460 |

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📝 Tips:

- Always round to the nearest 100 for estimation.
- Use column addition with place value (Th, H, T, O).
- Check your final answer against the estimate — they should be close!

Let me know if you'd like this printed or formatted into a worksheet!