"((7 - 2 - 2)^2 )^2  - 2 = 79"

#Ruby22
def f0(number, log)
    return [number * number, "(" + log + ")^2 "]
end

def f1(number, log)
    return [number - 2, log + " - 2"]
end

end_num = 79
for n in 1..5
    for i in 0..2**n-1
        s = ("000000000000000000000000000000" + i.to_s(2))[-n..-1]
        start_num = 7
        log = start_num.to_s
        for k in 0..s.size-1

            start_num, log = f0(start_num, log) if s[k] == "0"
            start_num, log = f1(start_num, log) if s[k] == "1"
            # break if start_num > end_num
        end
        # p [start_num, log, s, n]
        if start_num == end_num then
            log += " = " + end_num.to_s
            p log
        end
    end
end