Addition worksheet with rounding exercises and a festive Christmas tree design.

Let's solve each part of this addition worksheet step by step. The task asks you to:

1. Estimate the answer by rounding each number to the nearest ten.
2. Then, solve the actual addition to check your estimate.

---

🔹 Rounding Rules:

- If the ones digit is 5 or more, round up.
- If the ones digit is less than 5, round down.

---

✔ a. 86 + 13

- 86 → 90 (since 6 ≥ 5, round up)
- 13 → 10 (since 3 < 5, round down)
- Estimated sum: 90 + 10 = 100

Now solve the actual problem:
- 86 + 13 = 99

✔ Check: Estimate (100) is close to actual (99)

---

✔ b. 32 + 61

- 32 → 30 (2 < 5, round down)
- 61 → 60 (1 < 5, round down)
- Estimated sum: 30 + 60 = 90

Actual sum:
- 32 + 61 = 93

✔ Check: Estimate (90) is close to actual (93)

---

✔ c. 49 + 37

- 49 → 50 (9 ≥ 5, round up)
- 37 → 40 (7 ≥ 5, round up)
- Estimated sum: 50 + 40 = 90

Actual sum:
- 49 + 37 = 86

✔ Check: Estimate (90) is close to actual (86)

---

✔ d. 64 + 22

- 64 → 60 (4 < 5, round down)
- 22 → 20 (2 < 5, round down)
- Estimated sum: 60 + 20 = 80

Actual sum:
- 64 + 22 = 86

✔ Check: Estimate (80) is close to actual (86)

---

✔ e. 91 + 59

- 91 → 90 (1 < 5, round down)
- 59 → 60 (9 ≥ 5, round up)
- Estimated sum: 90 + 60 = 150

Actual sum:
- 91 + 59 = 150

✔ Check: Estimate (150) matches actual (150) perfectly!

---

✔ f. 28 + 92

- 28 → 30 (8 ≥ 5, round up)
- 92 → 90 (2 < 5, round down)
- Estimated sum: 30 + 90 = 120

Actual sum:
- 28 + 92 = 120

✔ Check: Estimate (120) matches actual (120) perfectly!

---

✔ Final Answers:

| Problem | Rounded Numbers | Estimated Sum | Actual Sum |
|--------|------------------|----------------|------------|
| a. | 90 + 10 | 100 | 99 |
| b. | 30 + 60 | 90 | 93 |
| c. | 50 + 40 | 90 | 86 |
| d. | 60 + 20 | 80 | 86 |
| e. | 90 + 60 | 150 | 150 |
| f. | 30 + 90 | 120 | 120 |

---

🎄 Summary:

You can now fill in the blanks on the worksheet with these rounded values and sums.

For example:

> a. 86 round to 90
> + 13 round to 10
> 100
> Actual: 86 + 13 = 99

Repeat similarly for others.

Let me know if you'd like this formatted as a printable answer sheet!