Cross multiplication is not how you multiply fractions in 6th grade; instead, you multiply across. In sixth grade, when multiplying fractions, you multiply the numerators together and the denominators together. Here's a detailed explanation:
Multiplying Fractions: The "Across" Method
The method for multiplying fractions in 6th grade involves multiplying the numerators and denominators directly, as demonstrated in the provided video reference.
Here's how it works:
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Identify Numerators and Denominators: In any fraction (e.g., 1/2), the top number is the numerator (1), and the bottom number is the denominator (2).
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Multiply Numerators: Multiply all the numerators of the fractions you are working with. This will give you the new numerator for your answer.
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Multiply Denominators: Multiply all the denominators of the fractions you are working with. This will give you the new denominator for your answer.
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Simplify (if needed): Reduce the resulting fraction to its simplest form if the numerator and denominator have common factors.
Example:
Let's look at the example in the reference of 1/2 times 4/3:
- Step 1: The numerators are 1 and 4, and the denominators are 2 and 3.
- Step 2: Multiply the numerators: 1 * 4 = 4.
- Step 3: Multiply the denominators: 2 * 3 = 6.
- Step 4: The resulting fraction is 4/6, which can be simplified by dividing both the numerator and denominator by 2. This gives us 2/3.
Therefore, 1/2 * 4/3 = 2/3
Important Points:
- No Cross Multiplication For Multiplying: Unlike solving proportions, you do not cross multiply when multiplying fractions.
- Focus on Straight Multiplication: You multiply the tops (numerators) and then multiply the bottoms (denominators).
- Simplification: Always reduce your final answer to the simplest form.
Summary
| Step | Description | Example (1/2 * 4/3) |
|---|---|---|
| 1 | Identify numerators/denominators | Numerators: 1, 4; Denominators: 2, 3 |
| 2 | Multiply numerators | 1 * 4 = 4 |
| 3 | Multiply denominators | 2 * 3 = 6 |
| 4 | Simplify if possible | 4/6 = 2/3 |
