Do two natural numbers always have a gcf

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Is triangle jkl congruent to triangle rst? if so, what is the scale factor?

David leaves his house to go to school. he walks 200 meters west and 300 meters north. how far is david from his original starting point?