Rounding Decimals to a Whole Number (Year 5) | CGP Plus - Free Printable

Let's solve the problem step by step based on the image you provided. The worksheet is about rounding decimals using a number line.

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Question 1: Show the position of these numbers on the number line

We are given the following decimal numbers:
- 2.3, 3.75, 2.5, 3.9, 3.4, 2.85

And a number line from 2 to 4, marked in tenths (0.1 increments).

#### Step-by-step placement:

- 2.3: Already shown — it’s between 2 and 3, three-tenths from 2.
- 3.75: Between 3 and 4. It’s halfway between 3.7 and 3.8 → place it at 3.75
- 2.5: Midway between 2 and 3 → mark at 2.5
- 3.9: Close to 4, just 0.1 before 4 → mark at 3.9
- 3.4: Between 3 and 4, four-tenths from 3 → mark at 3.4
- 2.85: Between 2.8 and 2.9 → closer to 2.9, but not quite there → mark at 2.85

✔ So, we draw small dots or marks on the number line at these positions.

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Part b) Round to the nearest whole number using the number line

Use the number line to determine which whole number each decimal is closest to.

| Number | Rounded to Nearest Whole Number |
|--------|-------------------------------|
| 2.3 | 2 ✔ (closer to 2 than 3) |
| 3.75 | 4 (since 3.75 is more than 3.5) |
| 3.4 | 3 (closer to 3 than 4) |
| 2.5 | 3 (exactly halfway — round up) |
| 3.9 | 4 (very close to 4) |
| 2.85 | 3 (closer to 3 than 2? Wait: 2.85 is 0.15 from 3, and 0.85 from 2 → so yes, closer to 3) |

Wait! Let's double-check:
- 2.85: Distance to 2 = 0.85, distance to 3 = 0.15 → so closer to 3
- But 2.5: Standard rule — halfway rounds up → so 3

So correct rounding:
- 2.3 → 2
- 3.75 → 4
- 3.4 → 3
- 2.5 → 3
- 3.9 → 4
- 2.85 → 3

✔ Fill in the blanks accordingly.

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Question 2: Show the position of these decimals on the number line (5 to 7)

Numbers:
- 5.25, 5.4, 6.05, 6.7, 5.55, 6.4

Number line from 5 to 7, with tick marks every 0.1 (tenths).

#### Positioning:
- 5.25: Between 5.2 and 5.3 → halfway → mark at 5.25
- 5.4: At 5.4
- 6.05: Just above 6 → very close to 6
- 6.7: Between 6.7 and 6.8 → at 6.7
- 5.55: Between 5.5 and 5.6 → halfway → mark at 5.55
- 6.4: At 6.4

Now, fill in the table:

> Put the numbers in the table based on whether they round to 5, 6, or 7.

Recall:
- Round to nearest whole number:
- If decimal part < 0.5 → round down
- If ≥ 0.5 → round up

Let’s evaluate each:

| Number | Decimal Part | Round To |
|--------|--------------|---------|
| 5.25 | 0.25 < 0.5 → 5 | Rounds to 5 |
| 5.4 | 0.4 < 0.5 → 5 | Rounds to 5 |
| 6.05 | 0.05 < 0.5 → 6 | Rounds to 6 |
| 6.7 | 0.7 ≥ 0.5 → 7 | Rounds to 7 |
| 5.55 | 0.55 ≥ 0.5 → 6 | Rounds to 6 |
| 6.4 | 0.4 < 0.5 → 6 | Rounds to 6 |

So now fill the table:

| Rounds to 5 | Rounds to 6 | Rounds to 7 |
|-------------|-------------|-------------|
| 5.25 | 6.05, 5.55, 6.4 | 6.7 |
| 5.4 | | |

Wait — 5.4 also rounds to 5!

So:

- Rounds to 5: 5.25, 5.4
- Rounds to 6: 6.05, 5.55, 6.4
- Rounds to 7: 6.7

✔ Fill the table accordingly.

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Question 3: Match the decimals to the correct description

We have three descriptions:
- Rounds to 3
- Rounds to 4
- Rounds to 5

Decimals: 3.43, 3.1, 4.5, 3.8, 2.72, 4.68

Let’s round each:

| Number | Round to? | Reason |
|--------|-----------|--------|
| 3.43 | 3 | 0.43 < 0.5 → down |
| 3.1 | 3 | 0.1 < 0.5 → down |
| 4.5 | 5 | 0.5 → round up |
| 3.8 | 4 | 0.8 ≥ 0.5 → up |
| 2.72 | 3 | 0.72 ≥ 0.5 → up |
| 4.68 | 5 | 0.68 ≥ 0.5 → up |

So group them:

- Rounds to 3: 3.43, 3.1, 2.72
- Rounds to 4: 3.8
- Rounds to 5: 4.5, 4.68

✔ Now match accordingly.

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✔ Final Answers Summary

#### 1a) Number Line Positions
Mark:
- 2.3 → near 2.3
- 3.75 → between 3.7 and 3.8
- 2.5 → midway between 2 and 3
- 3.9 → just below 4
- 3.4 → between 3 and 4, 4/10 along
- 2.85 → between 2.8 and 2.9

#### 1b) Rounding to Nearest Whole Number
- 2.3 → 2
- 3.75 → 4
- 3.4 → 3
- 2.5 → 3
- 3.9 → 4
- 2.85 → 3

#### 2) Table: Rounding from 5–7
| Rounds to 5 | Rounds to 6 | Rounds to 7 |
|-------------|-------------|-------------|
| 5.25, 5.4 | 6.05, 5.55, 6.4 | 6.7 |

#### 3) Matching Descriptions
- Rounds to 3: 3.43, 3.1, 2.72
- Rounds to 4: 3.8
- Rounds to 5: 4.5, 4.68

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