Question

Which number is a composite number?

2

thirteen

twenty-nine

eighty-one

Answer 1

hmm i think 29

Answer 2

29

Answer 3

thank you

Answer 4

a composite number can be factored into prime factors
If a number is not prime, it is composite.

here is a list of primes.
http://primes.utm.edu/lists/small/1000.txt

Answer 5

Notice that 3 out of 4 of your numbers are on that prime number list.

also notice that 9*9 = 81
(which means 81 can be factored... so it is not prime)
in fact 81= 3*3*3*3 (and 3 is prime)