Doubling Other Fractions: Watch It!
How do you double a fraction that has a numerator other than 1, such as 2/3?
You can still use unit fractions to think about how to double 2/3. Consider this: if 1 whole is divided into 3 sections, each section is 1/3. And 2/3 is the same as 2 sections of 1/3. You know that 2 doubled is 4. So 2/3 doubled is the same as 4 sections of 1/3, or 4/3.
Click below to watch a video of the two girls doing this problem.
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Chocolate and More Chocolate
You can also use a model to understand how to double 2/3. Picture A shows a candy bar broken into 3 equal sections, or thirds. Each part is 1/3. Picture B shows 2 sections, or 2/3, of the bar. Picture C shows that 2/3 has been doubled—now there are 4 total sections of 1/3 instead of 2. Picture D shows that 4/3 is more than the whole chocolate bar that you started with! It is 1 bar and 1/3 of another bar, or 1 1/3.
In the video, the two girls doubled 2/3 to make it 4/3, or 1 1/3. In one to two sentences, explain how you would double the fraction 2/7.
