vertikaal cijferen

Exercise 1: Add vertically to 999 without memorizing (2 digits).
Exercise 2: Add vertically to 999 with memorize (2 digits).
Exercise 3: Add vertically to 9999 without memorizing (2 digits).
Exercise 4: Add vertically to 9999 with memorize (2 digits).
Exercise 5: Add vertically to 9999 with memorize (3 digits).
Exercise 6: Subtract vertically to 999 without borrowing (2 digits).
Exercise 7: Subtract vertically to 999 with derive (2 digits).
Exercise 8: Subtract vertically to 9999 without borrowing (2 digits).
Exercise 9: Subtract vertically to 9999 with derive (2 digits).
Exercise 10: Multiply vertically to 999 with memorization.
Exercise 11: Multiply vertically to 9999 with memorization.
Exercise 12: Multiply vertically to 99999 with memorization.
Exercise 13: Dividing vertically to 999 with Derivation (divide 3 digits, divider 1 digit).
Exercise 14: numerical mental arithmetic puzzle game, add up to 100 (2 digits).
Exercise 15: numerical mental arithmetic puzzle game, add up to 100 (3 digits).
Exercise 16: numerical mental arithmetic puzzle game, subtract up to 100.
Exercise 17: numerical mental arithmetic puzzle game, multiplying to 100.
Works best on tablets. Not so suitable for smartphones.