$ cat p5.sh #!/bin/bash.exe calc(){ if [ $1 -eq 10 ]; then [ $(expr $2) -eq 100 ] && echo ${2// /} else for x in ' + ' ' - ' ''; do calc $(expr $1 + 1) "${2}${x}${1}" done fi } calc 2 "1" $ time bash p5.sh 1+2+3-4+5+6+78+9 1+2+34-5+67-8+9 …