Subtract till 400

Calculate:

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

251	-	57	=
372	-	50	=
264	-	44	=
396	-	10	=
168	-	121	=
294	-	172	=
225	-	170	=
157	-	130	=
133	-	96	=
368	-	52	=