Subtract till 100

Calculate:

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

46	-	25	=
48	-	28	=
94	-	42	=
55	-	37	=
87	-	24	=
46	-	19	=
73	-	42	=
16	-	9	=
83	-	36	=
36	-	19	=