Subtract till 100

Calculate:

Number of examples:
Numerical difficulty:
Range of values:
Multiplicity:

87	-	15	=
64	-	37	=
88	-	43	=
50	-	14	=
46	-	8	=
69	-	18	=
94	-	49	=
91	-	10	=
30	-	10	=
50	-	3	=