Adding till 100

Calculate:

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

44	+	25	=
13	+	12	=
2	+	9	=
25	+	35	=
30	+	30	=
5	+	5	=
9	+	8	=
29	+	15	=
13	+	13	=
25	+	20	=