Answer:
1/2 or 0.5 in decimal
Explanation:
you would want to make the 3/10 eqale to 20/100 like it has to have the same denominatior which is 10x10 and 3x10. because 10x10 eqal to 100, and what you do to the bottom you have to do the same on the top. and then you add which becomes 30/100+20/100=50/100 and 50/100 =1/2 if you simplfiy.