Being able to convert fractions to decimals and then to percents is a valuable skill. The fraction may need to be simplified to a common fraction and then you may easily remember the equivalent decimal and percent.
12/20 Since 12/20 = 3/5, then 12/20 = 3/5 = 60/100 = 0.60 = 60% Easy steps!
24/40 24/40 = 12/20 = 6/10 = 0.60 = 60% Easy steps!
Convert these fractions to the most simplified fractions and then to a percent. The denominators are larger than or equal to 10. Strive for accuracy and then strive to increase your speed. Good luck and enjoy the challenge!