please help whenever my digimon digivolves it turns into numemon.

The reason you keep getting Numemon is that your Digimon hasn't met the right parameters to evolve into a strong Champion. Take it to the gym outside file city and train it. Go to the faqs/guides section of this site to see the requirments for getting the exact Champion you want. Since you have Numemon you could go to Toy Town and enter the robot house, a Monzaemon costume is there and Numemon is the only one who can wear it. He will digivolve into Monzaemon, who is an Ultimate. Another thing you can do is when a tournament at Greymon's Arena. They give Digivolution Items for winning certain tournaments.