Subtract till 100

Calculate:

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

67	-	32	=
26	-	6	=
56	-	29	=
50	-	45	=
44	-	40	=
42	-	27	=
59	-	9	=
53	-	48	=
67	-	42	=
43	-	22	=