Adding till 400

Calculate:

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

103	+	129	=
137	+	104	=
38	+	13	=
183	+	123	=
65	+	42	=
58	+	44	=
28	+	40	=
91	+	106	=
34	+	42	=
168	+	155	=