the factors of 40 are:

1,2,4,5,8,10,20 and 40

1x40=40
2x20=40
4x10=40
5x8=40
8x5=40
10x4=40
20x2=40
40x1=40
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the factors of 63 are:
1,3,7,9,21 and 63

1x63=63
3x21=63
7x9=63
9x7=63
21x3=63
63x1=63
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is 5 a factor of 65? yes.

is 7 a factor of 46? no.

is 9 a factor of 51? no.

is 6 a factor of 78? yes