So basically you line the numbers up lowest to largest and find the middle number:
Set A-
23, 23, 24, 67, 98, 101
So for this one 24 and 67 is in the middle... therefore you would do (24 + 67)/2 = 45.5
Median: 45.5
Set B-
21, 44, 45, 76, 89
Median: 45