The - sign is for subtraction. For example... pressing 3 - 2 then the = gives the result 1
Input is when you type with the calculator
"Calculator"
clear
yes you mean calculator. yes a calculator is there in the computer.
What does 4e-6 mean
memory/recall
13.076
The calculator.
not a number
all clear
Grand total
If you mean the pocket calculator, it is actually a computer.If you mean something like the abacus, of course the computer came after it.