Rohan use the model below to show 1.38 / 3 Rohan made an error in his model explain his era include the correct grouping for the model

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2 hours ago

To solve the problem of \( 1.38 \div 3 \) using a model, we first need to understand how to break down the number \( 1.38 \) and how to represent it visually for division.

1. **Understanding the Division**:
- When dividing \( 1.38 \) by \( 3 \), we can think of \( 1.38 \) as \( 1.00 + 0.38 \).
- We need to divide both parts by \( 3 \).

2. **Dividing Whole Numbers and Fractions**:
- **Whole Number Part**: \( 1.00 \div 3 = 0.3333... \) (repeating, which can be represented as \( \frac{1}{3} \)).
- **Decimal Part**: \( 0.38 \div 3 \).
- To divide \( 0.38 \) by \( 3 \), we can convert it into a fraction: \( 0.38 = \frac{38}{100} \).
- Now, divide: \( \frac{38}{100} \div 3 = \frac{38}{100} \times \frac{1}{3} = \frac{38}{300} = 0.12666... \) (approximately \( 0.127 \)).

3. **Combining Results**:
- Combining \( 0.3333... \) and approximately \( 0.127 \) gives \( 0.3333... + 0.127 \approx 0.460... \).

So, \( 1.38 \div 3 \approx 0.46 \) (more accurately, it could be \( 0.459 \) when considering the long division).

4. **Possible Errors in Rohan's Model**:
- If Rohan grouped \( 1.38 \) incorrectly, such as by trying to treat \( 1.38 \) as just โ€œ1โ€ and then assigning \( 0.38 \) incorrectly to the groups, it would lead to an incorrect result.
- Therefore, the correct grouping should clearly show that \( 1.38 \) is made of \( 1 \) whole and \( 0.38 \) (or \( 38 \) hundredths) and validate that they are grouped and divided properly among \( 3 \).

### Correcting the Model
- Visually, one could use a number line or blocks (where \( 1 \) is represented as 3 blocks of \( 0.3333... \) and then \( 0.38 \) is similarly divided) to show how each part of \( 1.38 \) is allocated among the \( 3 \) groups correctly, ensuring to represent the fraction and whole number parts appropriately.

Thus, the key was to ensure that the decimal and whole number were divided as their own components and combined afterward to get the correct result of the division.