Digit problems on the SAT appear different than normal variable problems because they usually contain capital letters instead of lowercase letters. 

 

   AB

+BA

------

1A7

 

The capital letter represents a digit regardless of the particular place value. A digit is simple any of the numbers from 0 to 9 - the numbers on a telephone pad. With digit problems, the trick is to guess and check. 

 

TIP: Make sure to use all of the information that is provided in the question. Test makers try to intentionally trick test takers with these types of questions. Also, it is important to remember that there is only a certain amount of time. If a problem is taking too long, it is much better to skip it and answer two easier questions to get the points. The SAT is all about getting the highest score possible - not about answering the most difficult questions.