Least Common Denominator Hack 1.2 + Redeem Codes

I need an app to save time while checking my kids math homework.
This app works but author put all their effort into displaying ads so the app is very lacking.
1) No built in keyboard so you always have to switch from the alphabet to numbers for every number you type (really wastes time)... And I do mean EVERY number
2) tons of wasted space on the screen which the dev fills up with ads annoying to say the least
3) no retina update, so fugly on my 6+
4) only space to add 2 numbers, sometimes you need the lowest common denominator on 4+ numbers