2 answers
(click or scroll down)
one easy way would be to shift the decimal point in both numbers enough places to make the smallest an integer. In this case, that would be 6 places:
27/9 = 3
In effect, that factors out 0.000001
.000001*27 ÷ .000001*9
Now you can cancel the factor of .000001 to get 27/9 = 3