Contact us
Choose a category below so we can get back to you as quickly as possible.
在1,2,4,5,13,14,15,19,20這些數中,奇數有(1,5,13,15,19),偶數有(2.4 14 20),質數有(2,5 13 19)合數有(4 14 15 20),既是合數又是偶數的數有(4 14 20)
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.