It's not a as flip is rotational, turn can also be rotational. I would go with slide as translation is a sideways motion
2-1/4
2/1=8/4 Multiply top and bottom by 4
8/4-1/4
7/4
1 3/4
The number of permutations of the 25 letters taken 2 at a time (with repetitions) is:

The number of permutations of the 9 digits taken 4 at a time (with repetitions) is:

Each permutation of letters can be taken with each permutation of digits, therefore the total number of possible passwords is:
It splits into 6 easerly so just make each part double walls as the pic shows