// 2/3 / 1/6 = 4/1
static_assert(
        std::is_same<
            std::ratio_divide<
                std::ratio<2, 3>::type,
                std::ratio<1, 6>::type
            >::type,
            std::ratio<4, 1>::type
        >::value,
        "ratio_divide does not work correctly");

// 2/3 * 1/6 = 1/9
static_assert(
        std::is_same<
            std::ratio_multiply<
                std::ratio<2, 3>::type,
                std::ratio<1, 6>::type
            >::type,
            std::ratio<1, 9>::type
        >::value,
        "ratio_multiply does not work correctly");

// 2/3 + 1/6 = 5/6
static_assert(
        std::is_same<
            std::ratio_add<
                std::ratio<2, 3>::type,
                std::ratio<1, 6>::type
            >::type,
            std::ratio<5, 6>::type
        >::value,
        "ratio_add does not work correctly");

// 2/3 - 1/6 = 1/2
static_assert(
        std::is_same<
            std::ratio_subtract<
                std::ratio<2, 3>::type,
                std::ratio<1, 6>::type
            >::type,
            std::ratio<1, 2>::type
        >::value,
        "ratio_subtract does not work correctly");