42 and 84
14, 28, 42, 56, 70, 84, 98
7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98
36 and 72
Just 77.
42 and so on
42 and 84
60 and 42 have no common multiples under 100.
The only common multiples of 6 & 7 up to 100 are 42 & 84.
Just 42.
14, 28, 42, 56, 70, 84, 98
21, 42, 63, 84.
21, 42, 63, 84
2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98,100
39, 78
' 1 ' is a factor of every whole number . . . . . 100 of them' 2 ' is a factor of every even number . . . . . 50 of them' 3 ' has 33 multiples up to 100 . . . . . 33 of them' 4 ' has 25 multiples up to 100 . . . . . 25 of them' 5 ' has 20 multiples up to 100 . . . . . 20 of them' 6 ' has 16 multiples up to 100 . . . . . 16 of them' 7 ' has 14 multiples up to 100 . . . . . 14 of them' 8 ' has 12 multiples up to 100 . . . . . 12 of them' 9 ' has 11 multiples up to 100 . . . . . 11 of themTotal . . . . . . . . . . . . . . . . . . . . . . . . . 281 one-digit factors in all whole numbers 1 to 100 .
I presume you mean what are all the multiples of 9 up to 100 (and not what are all the multiples of 9, 10, 11, ..., 100 of which there are infinitely many): 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99.