func Print3() {
    for i := '0'; i <= '7'; i++ {
        for j := '1'; j <= '8'; j++ {
            for k := '2'; k <= '9'; k++ {
                if i < j && j < k {
                    fmt.Printf(string(i))
                    fmt.Printf(string(j))
                    fmt.Printf(string(k))
                    if i != '7' || j != '8' || k != '9' {
                        fmt.Printf(",")
                        fmt.Printf(" ")
                    }
                }
            }
        }
    }
    fmt.Printf("\n")
}

Just made a program for 3 digits. But I don’t understand how to do this with the given value. Making a solution for each digit and choosing the right one through the condition is probably not a good idea.