Subtract till 400

Calculate:

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

247	-	195	=
330	-	177	=
266	-	24	=
195	-	71	=
294	-	160	=
110	-	45	=
147	-	145	=
296	-	23	=
231	-	13	=
130	-	78	=