I know how to do regular the ones

#!/bin/bash
NUM=$(( RANDOM % 10 ))
case $NUM in

0) echo "zero"
1) echo "one"
2 bla bla
3 bla
4 bla
5 bla
6 bla
7 esac
8
9
*
esac

But how do i use the read command in this
i want it to read a number and say it in letters
as when you type 5 it will echo five

thanks!