At the start of the website a subtraction problem was created.
Your task is to expand the first fraction to the given denominator.
So you get like fractions.
Then you can subtract them.

Example:

Click on check to check your answer.
Click on new to create a new problem.
Can you top 249 points?

Unlike fractions
subtraction - First exercise

In the exercises, it is sufficient
if you expand only one fraction.