20, 40 60, 80 and keep adding 20 until you get to 1400.
12.
4, 8, 12, 16, 20
Everything up to and including 20.
' 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 .
4, 8, 12, 16 and 20
10, 20, 30, 40, 50, 60, 70, 80, 90, 100.
All the multiples of 5 between 1 and 51 are: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 These add up to 275.
100 is the least common multiple of 20 and 25.
They are all te multiples of 6 within that range.
All multiples of 3 have digits that add up to a multiple of 3.
No odd numbers are multiples of 4.
There are none.