28 is a perfect number.
The two perfect numbers between 1 and 30 are: 6, 28
20 is between 10 and 30.
The number is 28.
30
36
-10
It is 28 I did that at school in year 6
The numbers between 10 and 30 that have exactly 5 factors are 16 and 25. The number 16 has factors 1, 2, 4, 8, and 16. The number 25 has factors 1, 5, 25, but since it is a perfect square, it also includes the repeated factor of 5. These are the only two numbers between 10 and 30 that have exactly 5 factors.
25 is a perfect square occurring between 20 and 30.
-20
30