On old mechanical typewriters, these are two keys (1 and !) you won't actually find on a QWERTY layout. The number row begins with a 2 above the Q, instead of 1.

So, how do you type 1 or !?

Well, 1 is easy. You use the lower case L. l vs 1. Before fonts, when the only type variation was pico or pica, 1 and l were indistinguishable.

The ! is not so obvious. You have to construct it. First you type a ' (single quote). Then you press back space and type a . (period) underneath.

Voila ' ^H .

Way way back, typewriters were very expensive and money was saved by not adding an additional key to the clockwork of arms and levers. At the turn of the century (the 20th century, that is), a typewriter cost $125. That's about $1,400 in today's dollars. So you can see why manufacturers tried to cut some corners to keep costs down.