math
posted by Kate .
How can you make 7 by only using the digits 1, 2, 3, and 4? You can put two numbers together (ie 12 or 34). You can use the operations: addition, subtraction, multiplication, (NO DIVISION!!), exponents, and parentheses any way you want!! Please help!!!!
I also need 13, 17, and 39!!!!!!!

1, 2, 3, 4 to make 7
(4+3)x(21)
13
(4x3)+(21)
17 and 39, I can't think of..keep playing around with the numbers.