The best estimate would be (-1)(1/2)(-1)(1)
Why?
(-4/5) = Really close to -1. The fraction -5/5 would = -1
(3/5) = Really close to 1/2
(-6/7) = Really close to -1. It is just -1/7 from being from -1
(5/6) = Really close to 1. It is just 1/6 from being 1