Creating a calculator script

Question

I am trying to make a calculator with a bash script. The user enters a number, chooses whether they wish to add, subtract, multiply or divide. Then the user enters a second

Answer 1

How about this

calc ()
{
  (( d = $1 ))
  echo $d
}

output

$ calc '6 + 2'
8

$ calc '6 - 2'
4

$ calc '6 * 2'
12

$ calc '6 / 2'
3