Subtract till 400

Calculate:

The number of examples:
Numerical difficulty:
Range of values:
Multiplicity:

82	-	40	=
187	-	12	=
44	-	34	=
33	-	16	=
253	-	147	=
86	-	46	=
121	-	15	=
217	-	78	=
331	-	93	=
146	-	23	=