Prime numbers within 20 are______ The total number within 20 is______ The odd numbers within 20 are______ Even numbers within 20 have______ ．

Prime numbers within 20 are______ The total number within 20 is______ The odd numbers within 20 are______ Even numbers within 20 have______ ．

According to the definition of prime number, composite number, even number and odd number, prime numbers within 20 are: 2, 3, 5, 7, 11, 13, 17 and 19; composite numbers within 20 are: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18 and 20; odd numbers within 20 are: 1, 3, 5, 7, 9, 11, 13, 15, 17 and 19; even numbers within 20 are: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20; so the answer is: 2 、3、5、7、11、13、17、19；4、6、8、9、10、12、14、15、16、18、20；1、3、5、7、9、11、13、15、17、19；0、2、4、6、8、10、12、14、16、18、20．