One and three
3. 7x3= 21 12x3= 36
1 and 3 are the common factors of 21 and 36.
21/7 = 3 21/3 = 7 36/2 = 18 36/4 = 9 36/6 = 6 36/12 = 3 36/18 = 2 and, of course, both 21 and 36 can be divided by 1 and themselves
3 goes into 36 and 63 evenly.
2 is one such number.
1
4
To find a number that goes into both 36 and 13, we can look for their greatest common divisor (GCD). The GCD of 36 and 13 is 1, since 13 is a prime number and does not divide 36. Therefore, the only integer that goes into both 36 and 13 is 1.
Nothing.. Because 21 is a Prime number
1 and 3.
Because 2 goes into 36 without remainder. 36 = 2*18
That number is 9.