Difference between varied and varying as adjectives

I have seen "varied" and "varying" used in similar sentences online and in newspapers. For example,

(1a) People express varied opinions about nuclear weapons.

(1b) People express varying opinions about nuclear weapons.

(2a) He teaches students with varied learning needs.

(2b) He teaches students with varying learning needs.

Could you please explain the difference in meaning between the two words? Thank you very much.