Adding till 400

Calculate:

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

238	+	130	=
78	+	67	=
184	+	149	=
29	+	10	=
153	+	226	=
31	+	39	=
137	+	77	=
151	+	141	=
123	+	255	=
117	+	279	=