How do you find all the factors of the number 45?

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Answer 1 · 2016-12-19T08:55:24

the factors of #" "45:{1,3,5,9,15,45}#

The best way would be to systematically find pairs of number that multiply to give 45

so#" "color(red)1xxcolor(red)(45)=45#

#45" "#ends in a #5# so #""5""# must be a factor

#" "color(red)5xxcolor(red)(9)=45#

we can now use factors of the factors where possible

#9=3xx3" "# we can use #3#

#" "color(red)3xxcolor(red)(15)=45#

#15#has #" "3" "#&#" "5" "#which we have already used

any other combination gives a number greater than half of #" "45" "# so we have found them all

so all the factors of #" "45:{1,3,5,9,15,45}#