Adding till 400

Calculate:

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

101	+	285	=
136	+	140	=
121	+	76	=
157	+	108	=
32	+	54	=
151	+	77	=
153	+	91	=
163	+	237	=
51	+	69	=
57	+	37	=