PI="3,1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679"

i=4
echo -n "PI ~= "
echo ${PI:0:10}
while true; do
    echo "Press <enter> and type a PI approximation."
    read -n 1
    clear
    read -p "3," -e mypi
    i=1
    mypi=3,$mypi
    while [ "${mypi:$i:1}" = "${PI:$i:1}" ]; do
	i=$(($i + 1))
    done
    echo ${PI:0:$i}""${PI:$i:2}""
    echo -n "($(($i-1))) "
done