ALABEMOS  This is a nice simple app that does just what it says. If you are a teacher working with elementary school children you'll find it handy. You can enter how many problems you want on the sheet,up to 20 for algebra, and up to 50 for the four basic operations and how many sheets you want. If you have 25 students, you can generate 25 different sheets on the same level with one click. And for the busy teacher, you can print an answer sheet to check the problems with as well.

There are three choices of difficulty: simple, average, and advanced. Problems are generated for the basic operations and for algebra. You can have the problems presented horizontally or vertically (exception: algebra horizontally only, of course.)

The only thing I didn't like, was that problems stay exactly the same, whether you want 10 or 50. So if you only have a few problems, you use a tiny bit of space, and leave most of the page blank. With younger children who may need to have smaller amounts of problems and larger fonts, I prefer to enlarge and spread out the problems, making them easy for newer readers.

Overall, it is a handy little program, and I expect to use it frequently.  
(Version 2.2.1)