The factor pairs of 215 are 1, 5, 43, and 215
There are 3 factor pairs of 245:245 = 1 x 245245 = 5 x 49245 = 7 x 35
The difference is between factor pairs and distinct factors. With square numbers, one of the factor pairs will be the same number twice. When listing the distinct factors, that number is only listed once.
The factor pairs of 260 are (260,1), (130,2), (65,4), (52,5), (26,10), and (20,13)
10 has two factor pairs:10 = 1 x 1010 = 2 x 5
80 has 5 factor pairs.
The factor pairs of 215 are 1, 5, 43, and 215
The factor pairs of 10 are 1*10, 2*5
1 and 5
1 and 5
5 and 1
80 has 5 factor pairs.
The factor pairs of 25 are 1 x 25 and 5 x 5
1 and 5
1 and 5
The factor pairs of 15 are 1 x 15 and 3 x 5.
The factor pairs of 205 are 1 x 205 and 5 x 41.