Yet another FooBarQix solution

foobarqix.sh

#!/bin/sh
_() {
   [ $(expr $V % $1) == 0 ] && R=$(echo $R$2)
}

foobarqix() {
   _ 3 "Foo";_ 5 "Bar";_ 7 "Qix"
   R=$(echo $R$V | sed -e 's/3/Foo/g' | sed -e 's/5/Bar/g' | sed -e 's/7/Qix/g' | sed -e 's/[0-9]//g')
   [ "Z$R" == "Z" ] && R=$V
}

for i in {1..100} ; do
   export R=""; export V=$i
   foobarqix
   echo $i" : "$R
done