(-5/-6)×а×(-4/-5)×в×(3/8)
(-5/-6) * а * (-4/-5)*b *(3/8) = = ( ⁵/₆ * ⁴/₅ * ³/₈) *ab = = ( ⁵*⁴*³ / ₆*₅*₈ ) *ab = = ( ¹*¹*¹/ ₂* ₁*₂ ) ab = = ¹/₄ * ab = 0.25ab