Adding till 400

Calculate:

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

43	+	27	=
8	+	1	=
104	+	81	=
14	+	17	=
120	+	109	=
33	+	33	=
99	+	103	=
133	+	211	=
102	+	172	=
57	+	90	=