A while back I taught Lula Mae my phone number and Charlies phone number. I think that a child should know a few basic things to keep them safe (address, phone numbers, parents full names). I found a great way to help teach Lula Mae how to type our phone numbers....
a calculator! It works great because I can ask her to "dial" it, then check the number when she is done. Plus, she can see it too and check her work. Just one more use for an everyday household item :-)