Question

A recipe calles for 4/5 cup of sugar and 1/3 of cinnamon. How much more sugar is needed than cinnamon.

Answer 1

To find the difference you would need to make the denominator equal so I changed it to 15 and the difference would be 7/15  

Answer 2

Before you can compare, you need to find common denominators. The common denominator of $\frac{4}{5}$ and $\frac{2}{3}$ is 15. So the fractions are now: $\frac{12}{15}$ and $\frac{5}{15}$. Then subtract to find the difference:
$\frac{12}{15} - \frac{5}{15} = \frac{7}{15}$ more cups of sugar are needed.

Hope that helps.