Adding till 400

Calculate:

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

57	+	54	=
227	+	148	=
105	+	82	=
178	+	187	=
29	+	19	=
91	+	90	=
58	+	71	=
54	+	82	=
163	+	132	=
256	+	123	=