Subtracting Fractions with Different Denominators

If you have $\frac{3}{4}$ of a pizza and you eat $\frac{1}{2}$ of it, how much pizza is left?

What is $\frac{3}{5} - \frac{1}{3}$?

A baker used $\frac{5}{6}$ of a cup of sugar for cookies and $\frac{1}{2}$ a cup for cake. How much sugar did he use in total?

If $\frac{7}{10}$ of a book is read and $\frac{1}{5}$ of it is reread, how much of the book is left unread?

If a recipe calls for $\frac{3}{4}$ of a cup of milk and you accidentally put in $\frac{1}{3}$ of a cup, how much milk do you need to remove?

What is $\frac{5}{8} - \frac{1}{4}$?

What is $\frac{4}{5} - \frac{1}{2}$?

A class has $\frac{2}{3}$ of its students present, and $\frac{1}{4}$ of those students leave. What fraction of the class is still present?

If you have $\frac{9}{10}$ of a meter of ribbon and you cut off $\frac{3}{5}$ of a meter, how much ribbon do you have left?

What is $\frac{6}{7} - \frac{2}{5}$?