math help. the 4 game

I need help in math. okay so this is a question. How can I get the answer 13 using the number 4 only with any operations but you have to use the number 4 as low as possible. I got the equation ....
44/4 + radical 4 . u got a shorter way? also if you can give me the equations for the numbers 15,7,9. i got the equations but i wont the shortest one.

if you can then from 1-20. i want to get the shortest equations.

I think that is the shortest way.

I think it is as well. BTW, lost the game.

FFFAWK! Thank you Fang, the ONE time I choose to goto this forum, thank you...

learn to pronounce the bloomin subject properly kid

He said it correct: Math. In the US that's how it's ponounced.