Simple, here's an example (Skip to the bottom if you'd rather just see the answer, but this is detailed instructions on how to solve this problem and similar. Skip.... Only if you dare!):
Jimmy has 10 apples, he gives 3 to his mother for a pie. How many apples does Jimmy have now?
This question is basically the same thing, but worded differently
To find the answer, you simply have to subtract the amount given from the total amount, so, 10 - 3, which equals to 7. Jimmy now has 7 apples. Easy, right?
Here's another example (Which is a bit more related to your question):
Karen owns a business (Jason plays a game). Karen's highest selling month earned her $50,782 (Jason scored 14,568 points playing a game). Karens rival companys highest selling month earned them $39,984 (The all-time high score is 22,402 points). How much more money did Karen earn than her rival (How much greater is the all time high score than Jasons score)?
To find the answer, you ALWAYS subtract the smaller number from the bigger number to find the difference, so, in Karens case it would be $50,782 - $39,984 = $10,798 whereas with Jason it would be 22,401 - 14,568 = 7833.
So, the all-time high score is 7833 points higher than Jasons high score.
I really hope this helps, and ask me questions if you have any.