Homework help!! Which one does not belong?

Question

In each set of number does not belong. Circle this number and explain why it does not belong with the others.(Consider such things as primes, composites,factors,and even spelling!) Then replace the number that does not belong with a number that does.

9,16,20,25.

313,1001,111,1313.

Answer 1

maybe 20 because it doesn't have a square root?

it could be 9,16,25,36 in that case...

for the other one, maybe 313 because the rest start with 1

131, 1001, 111, 1313

Answer 2

i would say 9 because the others go up +4,+5.

16+4=20 20+5=25