( - 25 / 18 ) × 49 / 10 × ( - 4 / 35 ) =
= ( - ) × ( - ) = +
= 25 / 10 × 49 / 35 × 4 / 18 =
= 5 / 2 × 7 / 5 × 2 / 9 =
= 7 / 9
