Adding till 400

Calculate:

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

66	+	89	=
89	+	162	=
107	+	92	=
30	+	25	=
57	+	39	=
70	+	82	=
129	+	70	=
161	+	168	=
35	+	20	=
61	+	73	=