Alejandra seems to have a good foundation in math. With the SAT though, there are some topics which she has not seen in a few years which are less familiar. Also, the test often includes answers that you would arrive at if you make a common mistake.
For example, on the first problem we looked at, she went through the problem quickly but made a small mistake with overlooking a negative sign. That means she understands the process, however, she would have gotten the wrong answer there.
We went over the formula to get the sum of the interior angles of an n-gon, something like that could show up.
Also went over how adding 10% can be done more efficiently by multiplying by 1.1, etc. That was a useful technique for the test at times.