Subtract till 100

Calculate:

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

19	-	6	=
56	-	46	=
82	-	28	=
75	-	12	=
49	-	37	=
52	-	38	=
68	-	23	=
46	-	7	=
32	-	20	=
54	-	22	=