Subtract till 400

Calculate:

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

251	-	81	=
240	-	63	=
226	-	58	=
170	-	139	=
374	-	117	=
34	-	11	=
364	-	183	=
385	-	74	=
371	-	42	=
384	-	81	=