This leads off in interesting directions, though. For example, people complain that students shouldn't just use calculators, but in the developed world, the chances of not having access to a working calculator on a phone or computer are very small (that said, it's good to know what the machine is doing for you, even if you don't want to do it yourself). Compare that to phone numbers - even a generation ago, it was common to have memorized half-dozen 10 digit phone numbers for friends and family members. Are we diminished somehow now for having offloaded that to machines? Or was it work we shouldn't have ever had to take on?
>>blacks+(OP)
Specifically regarding calculators, the idea is that knowing how to calculate aids in understanding later math that depends on calculation.
Phone numbers don't lead to other interesting ideas, that I can think of. Didn't dialing originally work by just picking up the handset and telling the operator who you wanted to talk to?