a=(1 2 3)
b=(10 11 12)
readarray -t c < <(for idx in "${!a[@]}"; do
echo "${a[$idx]} + ${b[$idx]}"
done | bc)
declare -p c
printf '%s\n' "${c[@]}"
YT0oMSAyIDMpCmI9KDEwIDExIDEyKQoKcmVhZGFycmF5IC10IGMgPCA8KGZvciBpZHggaW4gIiR7IWFbQF19IjsgZG8KICBlY2hvICIke2FbJGlkeF19ICsgJHtiWyRpZHhdfSIKZG9uZSB8IGJjKQpkZWNsYXJlIC1wIGMKcHJpbnRmICclc1xuJyAiJHtjW0BdfSI=