1)
-9,25+(-3 1/5) = -9 1/4 - 3 1/5 = -9 5/20 - 3 4/20 = - 12 9/20 (или -12,45),
2)
-72+3 5/8+(-0,75) = -72 + 3 5/8 - 3/4 =
= -72 + 3 5/8 - 6/8 = -72 + 2 7/8 = - 69 1/8,
3)
15+(-9,46)+(-23/50) = 15 - 9 23/50 - 23/50 = 15 - 9 46/50 = 5 4/50 = 5 2/25 (или 5,08),
4)
-83,4+(-19 2/3)+(-4/15) = -83,4 - 19 10/15 - 4/15 = -83 2/5 - 19 14/15 =
= -83 6/15 - 19 14/15 = -102 20/15 = -103 5/15 = -103 1/3