-- basic equations

-- addition ( x + 5 = 2)
print("Give A")
a = io.read("*line")
if a ~= nil then
    print("Give B")
    b = io.read("*line")
end
if b ~= nil and a ~= nil then
    x = a - b
    print("x = " .. x)
end

function check()
    print("")
    print("a = " .. a)
    print("b = " .. b)
end

check()