9 and 15 only
'5' & '15' are odd numbers less than 20 , and are also multiples of '5'.
9 and 15 are the only two odd composite numbers less than twenty.
The odd prime numbers less than 20 are 3, 5, 7, 11, 13, 17, and 19.
All those not less than 20.
Seven of them.
First odd number greater than 20 is 21 Last odd number less than 200 is 199 → number of odd numbers between 20 and 200 is (199 - 21) ÷ 2 + 1 = 90
9 and 15
15 and 9 are both odd, composite numbers less than 20.
The first 20 odd numbers are: 13579111315171921232527293133353739.
Numbers that are prime can't be multiples of 10. Multiples of 10 can't be odd.
There are 5 odd numbers between 10 and 20: 11, 13, 15, 17, 19
It is impossible to add eight odd numbers together to get an even sum like 20. The sum of any odd numbers is always odd if an odd count of them is used, and it becomes even only when an even count is used. Since eight is an even number, the sum of eight odd numbers would be even, but it will still exceed 20 since the smallest odd number is 1, and the sum of eight 1s is 8, which is less than 20. Thus, there are zero ways to add eight odd numbers to achieve a sum of 20.