This app has students using a step by step process to solve the problems. First the student reads the problem and then labels the model appropriately.
Once they've checked to make sure they have identified the quantities properly, they then actually build the model to represent the problem. The app goes as far as telling the student the number of blocks should they need it.
I like this app because it has the student solve word problems in a step by step manner while giving immediate feedback. It does not make corrections for the students but it lets the student know what was done incorrectly and has the student make the correction. I also like that the app focuses on solving word problems since most students struggle to solve any type of word problem.