#!/bin/bash

sed 's/[a-z]//g' | \
  tee >(cut -c 1 > /tmp/firstdigits) | \
  tee >(rev | cut -c 1 > /tmp/seconddigits) > /dev/null | \
  paste - /tmp/firstdigits /tmp/seconddigits -d "" | \
  paste -sd+ | \
  bc