Number munchers is intended to teach basic math skills including addition, subtraction, multiplaction, division, as well as equality, inequality and prime numbers. Anyone could play this to sharpen their math skills but this game would be the best for kids between the ages of 9 and 14.
Side note: If you are having problems getting this game to run smoothly, press Ctrl+F12 multiple times. You should see this in the other DosBox window:
CPU:3500 cycles
CPU:4000 cycles
CPU:4500 cycles
....
and so on.
I use it at 25000 cycles, and it will probably be dfiferent for you, just keep pressing Ctrl+F12 over and over until it runs smoothly.