Math worksheet for estimating addition by rounding numbers to the nearest ten.

Worksheet titled "Estimating the addition" with 20 addition problems requiring rounding to the nearest ten.

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You're working on a worksheet titled “Estimating the addition”, which asks you to:

> Round each whole number to the nearest ten, then add the rounded numbers.

This is an estimation exercise — not exact calculation — so we round *before* adding.

---

📌 How to Round to the Nearest Ten:

- Look at the ones digit (the digit in the ones place).
- If it’s 0–4, round down.
- If it’s 5–9, round up.

Examples:
- 45 → ones digit is 5 → round up → 50
- 23 → ones digit is 3 → round down → 20
- 76 → ones digit is 6 → round up → 80

---

Now let’s solve each problem step by step.

---

✔ Problem 1:

```
45 → 50
+23 → +20
———
70
```
✔ Already filled in correctly.

---

✔ Problem 2:

```
75 → 80 (round up)
+48 → +50 (round up)
———
130
```
➡️ Answer: 130

---

✔ Problem 3:

```
66 → 70 (round up)
+23 → +20 (round down)
———
90
```
➡️ Answer: 90

---

✔ Problem 4:

```
55 → 60 (round up)
+42 → +40 (round down)
———
100
```
➡️ Answer: 100

---

✔ Problem 5:

```
73 → 70 (round down)
+45 → +50 (round up)
———
120
```
➡️ Answer: 120

---

✔ Problem 6:

```
89 → 90 (round up)
+33 → +30 (round down)
———
120
```
➡️ Answer: 120

---

✔ Problem 7:

```
23 → 20 (round down)
+45 → +50 (round up)
———
70
```
➡️ Answer: 70

---

✔ Problem 8:

```
76 → 80 (round up)
+37 → +40 (round up)
———
120
```
➡️ Answer: 120

---

✔ Problem 9:

```
34 → 30 (round down)
+25 → +30 (round up)
———
60
```
➡️ Answer: 60

---

✔ Problem 10:

```
46 → 50 (round up)
+39 → +40 (round up)
———
90
```
➡️ Answer: 90

---

✔ Problem 11:

```
76 → 80 (round up)
+25 → +30 (round up)
———
110
```
➡️ Answer: 110

---

✔ Problem 12:

```
78 → 80 (round up)
+23 → +20 (round down)
———
100
```
➡️ Answer: 100

---

✔ Problem 13:

```
67 → 70 (round up)
+39 → +40 (round up)
———
110
```
➡️ Answer: 110

---

✔ Problem 14:

```
22 → 20 (round down)
+17 → +20 (round up)
———
40
```
➡️ Answer: 40

---

✔ Problem 15:

```
67 → 70 (round up)
+34 → +30 (round down)
———
100
```
➡️ Answer: 100

---

✔ Problem 16:

```
85 → 90 (round up)
+49 → +50 (round up)
———
140
```
➡️ Answer: 140

---

✔ Problem 17:

```
89 → 90 (round up)
+33 → +30 (round down)
———
120
```
➡️ Answer: 120

---

✔ Problem 18:

```
67 → 70 (round up)
+33 → +30 (round down)
———
100
```
➡️ Answer: 100

---

✔ Problem 19:

```
56 → 60 (round up)
+32 → +30 (round down)
———
90
```
➡️ Answer: 90

---

✔ Problem 20:

```
87 → 90 (round up)
+67 → +70 (round up)
———
160
```
➡️ Answer: 160

---

## 🎯 Final Answers Summary:

| Problem | Rounded Addends | Estimated Sum |
|---------|----------------------|---------------|
| 1 | 50 + 20 | 70 |
| 2 | 80 + 50 | 130 |
| 3 | 70 + 20 | 90 |
| 4 | 60 + 40 | 100 |
| 5 | 70 + 50 | 120 |
| 6 | 90 + 30 | 120 |
| 7 | 20 + 50 | 70 |
| 8 | 80 + 40 | 120 |
| 9 | 30 + 30 | 60 |
| 10 | 50 + 40 | 90 |
| 11 | 80 + 30 | 110 |
| 12 | 80 + 20 | 100 |
| 13 | 70 + 40 | 110 |
| 14 | 20 + 20 | 40 |
| 15 | 70 + 30 | 100 |
| 16 | 90 + 50 | 140 |
| 17 | 90 + 30 | 120 |
| 18 | 70 + 30 | 100 |
| 19 | 60 + 30 | 90 |
| 20 | 90 + 70 | 160 |

---

✔ All problems solved! You can now fill in the blanks on your worksheet with these estimated sums.

Let me know if you’d like to check the actual sums too for comparison!

Parent Tip: Review the logic above to help your child master the concept of estimate sums and differences worksheet.

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