RPN Tutorial Exercise 3

The TAB key provides a way to operate on the number in level 2.

3:  10         3:  10         4:  10         3:  10         3:  10
2:  20         2:  30         3:  30         2:  30         2:  21
1:  30         1:  20         2:  20         1:  21         1:  30
    .              .          1:  1              .              .
                                  .

                  TAB             1              +             TAB

Similarly, M-TAB gives you access to the number in level 3.

3:  10         3:  21         3:  21         3:  30         3:  11
2:  21         2:  30         2:  30         2:  11         2:  21
1:  30         1:  10         1:  11         1:  21         1:  30
    .              .              .              .              .

                  M-TAB           1 +           M-TAB          M-TAB