Radio Tuning Question

[LTCSZ]

OK, this might be the ultimate dumb question, but here goes; When tuning a radio from the keyboard, I can increase and decrease one digit on the readout after I select the radio/adf/transponder etc...How do I change to the other digits? Hope the question is clear and not too dumb...(I know the answer is probably simple and right in front of me, but I'm having a series of Senior Moments...

Thanks,

Steve