5.45 written as a mixed number is 5 9/20. You get that by well first 5 is a whole number so put that by itself. Then .45 is really 45/100. You reduce that because both of them can be reduced by 5. Reduce them to get 9/20. After that, just put the pieces together. Put 5 by itself and 9/20 to get 5 9/20.