What's the difference between "complicated" and "complex"

[japanjapan]

1 Even with the sun or stars to steer by the problems of navigation are more ________ than they might seem at first.



2 The composer transformed a simple folk tune into a ______ set of variations.

which should be filled with "complicated" and which "complex"?
what's the difference?
thanks a lot, teachers.

[Temico]

1 Even with the sun or stars to steer by the problems of navigation are more ________ than they might seem at first.



2 The composer transformed a simple folk tune into a ______ set of variations.

which should be filled with "complicated" and which "complex"?
what's the difference?
thanks a lot, teachers.

1) Even with the sun or stars to steer by, the problems of navigation are more complex than they might seem at first.
( "complex" means "difficult to understand or explain because there many different parts" )

2) The composer transformed a simple folk tune into a complicated set of variations
( "complicated" is the opposite of "simple" )

( BTW, I am not a teacher; I am only a student.)