With 'CalcPrint', You can print calculation exercise sheets.
With 'CalcPrint', You can print 'math exercise sheets'.
You'll find much apps for calculation training in Google Play Store. But...
For kids, Ten-key is not necessarily well.
Paper is one of best interface.
In this app, You choose level and print excise sheet.
For example,
Addition (single-digit)
level 1 single-digit number + 1 or 1+single-digit number
level 2 single-digit number + (1 or 2) or (1 or 2)+single-digit number
level 3 single-digit + single-digit number (sum <=10)
level 4 single-digit + single-digit number
level 5 20-square calculation
Addition
level 1 double-digit number + single-digit number(vertical)
level 2 double-digit number + double-digit number(vertical)
.............................................
level 5 triple-digit number + triple-digit number
Internationalization
For example, Some countries use ":" as division symbol.
You can change all symbols and title as you like.