Multiplication till 400

Calculate:

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

20	×	13	=
8	×	6	=
20	×	20	=
9	×	4	=
18	×	19	=
21	×	11	=
17	×	15	=
15	×	14	=
14	×	12	=
10	×	13	=