Flash cards work! One can use them at their own pace and can move on when they feel comfortable, or they can skip around. You can also make handouts that show step-by-step how to perform a task.
Visual aids (aside from flash cards) are great also. Bring in different things to help with counting.
Are you teaching them that multiplication is also a form of addition and division is a form of subtraction? Some students never learn that. Though it make take longer to reach the answer, all that matters is that they reach the correct end.
For instance, 4x2= two sets of four. They can use 4+4. You can incorporate your visual aids here as well. I used beans. I prepared little baggies with about 200 beans each. The students counted out one set of 4 (4x1), one more set of 4 (4x2), so on an so forth.
For fractions, you can use fraction wheels or paper folding. Fraction wheels worked best for me. You can also use measuring cups. I am sure that she has seen a recipe before, even if she hasn't used one. You might be able to reach her by performing a simple cooking recipe.
I don't want to hog the thread, especially if you are already doing these things. If you need more tips, let me know. I've tried just about everything! (And I know how it feels when you try and try and don't seem to be reaching them....)
[soapbox] TEACHERS: Like Eclipse's student does, doesn't it tick you off when a student that you KNOW doesn't know/understand/comprehend the work that you assign, but have the NERVE to come to class with a 100% correct homework assignment, like they suddenly mastered the material overnight and you are going to be dumb enough to believe that they did the work themselves?
I can't tell you how many kids I have gone off on....[/soapbox]