Explain how to find which is greater 1/4 of 12 or 1/3 of 12

1/3 would be greater because 
1/3 of 12= 4 while 
1/4 of 12 = 3
to check your work you would get a calculator (if possible) and divide 3by 12 or 4 by 12 then if you get .33 (divide 3 by 12 like 3/12) its 1/3. if its .25 (divide 4 by 12 like 4/12) its 1/4