Adding till 400

Calculate:

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

68	+	106	=
156	+	154	=
102	+	78	=
20	+	14	=
7	+	8	=
72	+	73	=
47	+	51	=
128	+	157	=
70	+	47	=
1	+	2	=