Превращаем смешанные дроби в неправильные:
1) 3/16 * 1/3 * (-16/3) = -1/3
3/16 * 1/3 = 1/16
1/16 * (-16/3) = -1/3
2) (-2/19) * (-3/4) * (-19/2) = -3/4
(-2/19) * (-3/4) = 3/38
3/38 * (-19/2) = -3/4
3) 7/20 * (-3/17) * (-170/21) = -1/2
7/20 * (-3/17) = -21/340
21/340 * (-170/21) = -1/2
4) (-13,25) * (-75/13) * 2/3 = 76 целых 23/52
-13,25 * (-75/13) = переводим -13,25 в смешанную дробь: -13 целых 25/100 => -1325/100 * (-75/13) = 1325/4 3/13 = 3975/52 = 76 целых 23/52