The app assumes the student already knows their multiplication tables and are ready for the next step of multiplying two numbers together. So the app is designed to take students through each step of the multiplication process including carrying values.
The app shows a problem, with a green cursor in the ones position. The student types in the value, hits the enter button and if a number is carried the green cursor goes up above the next value. The student inputs the value, hits the enter button and the cursor moves to the tens position. The app continues until the problem is completed.
If at any point the student puts in an incorrect number, it shows red and the cursor will not move on. If they get it right, it says good job and the student clicks next for another practice problem.
If a student gets stuck there are both a hint and a help button available. The help button will put the correct digit in the spot and move the cursor on. The hint button types a message in the gray area above the number bad. It might say something like write the tens value of 8 x 5.
I see this app as usable from perhaps grade 4 on up. I would use it in my pre-algebra class for students who still have issues multiplying two numbers together. I plan to recommend this app to the special education department because I know she has students who struggle with multiplication in general and I believe it would help.