Subtract till 100

Calculate:

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

73	-	8	=
74	-	31	=
52	-	8	=
37	-	17	=
13	-	8	=
86	-	45	=
64	-	14	=
99	-	44	=
57	-	37	=
26	-	19	=