Subtract till 100

Calculate:

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

77	-	29	=
86	-	29	=
70	-	22	=
88	-	9	=
35	-	32	=
75	-	42	=
98	-	43	=
54	-	49	=
46	-	33	=
57	-	44	=