Adding till 100

Calculate:

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

16	+	15	=
14	+	12	=
48	+	39	=
11	+	9	=
16	+	14	=
27	+	33	=
39	+	26	=
42	+	50	=
46	+	30	=
21	+	27	=