Subtract till 400

Calculate:

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

181	-	132	=
289	-	74	=
209	-	172	=
171	-	127	=
181	-	114	=
370	-	120	=
66	-	22	=
173	-	156	=
391	-	48	=
266	-	121	=