This worksheet helps students practice counting by 10s, 100s, and 1000s using visual aids like an abacus and number sequences.

Let's solve each part of the worksheet step by step and explain the reasoning.

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Question 1: Abacus and Number Operations

We are given the number 4825 and asked to find:

#### a. 10 more than 4825
To add 10, we increase the tens place by 1:
4825 + 10 = 4835 ✔ (Already filled in correctly)

#### b. 100 less than 4825
Subtract 100 from 4825:
4825 - 100 = 4725

> Explanation: We subtract 1 from the hundreds place (8 → 7), so 4825 becomes 4725.

#### c. 1000 more than 4825
Add 1000 to 4825:
4825 + 1000 = 5825

> Explanation: Add 1 to the thousands place (4 → 5), so 4825 becomes 5825.

✔ Answers for Question 1:
a. 4835
b. 4725
c. 5825

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Question 2: Number Patterns

We need to identify the pattern and write the next three numbers.

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#### Pattern 1:
2347, 3347, 4347, 5347, 6347, 7347

- Each number increases by 1000.
- So next three numbers:
7347 + 1000 = 8347
8347 + 1000 = 9347
9347 + 1000 = 10347

✔ Answer: 8347, 9347, 10347

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#### Pattern 2:
8801, 8811, 8821, ___, ___, ___

- Look at the difference:
8811 - 8801 = 10
8821 - 8811 = 10
→ Increasing by 10 each time.

So:
- 8821 + 10 = 8831
- 8831 + 10 = 8841
- 8841 + 10 = 8851

✔ Answer: 8831, 8841, 8851

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#### Pattern 3:
3451, 3351, 3251, ___, ___, ___

- Difference:
3351 - 3451 = -100
3251 - 3351 = -100
→ Decreasing by 100 each time.

So:
- 3251 - 100 = 3151
- 3151 - 100 = 3051
- 3051 - 100 = 2951

✔ Answer: 3151, 3051, 2951

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Question 3: Missing Numbers

#### Row 1:
3861, 3761, 3661, 3561, 3461, 3361

- This is decreasing by 100 each time.
- Already completed correctly:
3861 → 3761 → 3661 → 3561 → 3461 → 3361

✔ All correct.

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#### Row 2:
581, 591, ____, ____, ____, 631

Let’s look at the pattern:
- 591 - 581 = +10
- So it’s increasing by 10 each time.

So:
- 591 + 10 = 601
- 601 + 10 = 611
- 611 + 10 = 621
- Then 621 + 10 = 631 ✔ matches last number

✔ Answer: 601, 611, 621

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#### Row 3:
____, 2111, ____, ____, 1811, 1711

We see:
- 1811 → 1711 = -100
- So likely decreasing by 100 each time.

Work backward:
- Before 2111: 2111 + 100 = 2211
- After 2111: 2111 - 100 = 2011
- Then: 2011 - 100 = 1911
- Then: 1911 - 100 = 1811 ✔
- Then: 1811 - 100 = 1711 ✔

So the sequence is:
2211, 2111, 2011, 1911, 1811, 1711

✔ Answer: 2211, 2011, 1911

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✔ Final Answers Summary:

#### Question 1:
a. 4835
b. 4725
c. 5825

#### Question 2:
- 8347, 9347, 10347
- 8831, 8841, 8851
- 3151, 3051, 2951

#### Question 3:
- Row 1: Correct as is
- Row 2: 601, 611, 621
- Row 3: 2211, 2011, 1911

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