[jameshart]

You can buy dedicated physical buttons and plug them into a computer. They’re called ‘keyboards’.

[avgcorrection]

Some even come in a format specialized for numerical data entry. They’re called “numpads”. :)

[PeterisP]

Some numpads even come with an attached specialized screen to show you what you entered and a bunch of other features - they're called "calculators" :)

[avgcorrection]

And the circle is complete :)