Subject: fractions to decimals and percents 2/5 , 4/8 , 4/10 , 3/5 , 6/8 , 7/7 (what is the decimal and percent for each) 1/5 , 1/10 , 1/8 , 1/1 (what is the decimal for each) 100 PERCENT, WHAT IS THE DECIMAL? The ratio of boys to girls in a class is 1:4. What percent of the class are girls? Hi, To express a common fraction such as  2/5 as a decimal fraction you divide the denominator into the numerator. In this case, dividing 5 into 2 gives 0.4, thus  2/5 = 0.4. The word percent is formed from the words per meaning for each or for every (miles per hour) and the word cent which comes from the Latin word centum, meaning 100. Thus to write  2/5 as a percent you need to find a fraction, equivalent to  2/5, with a denominator of 100. That is find ? so that  2/5 = ?/100 Using your knowledge of fractions you can see that ? = 40. Thus  2/5 = 40/100 or  2/5 is 40 per one-hundred, that is 40 percent. To say the "ratio of boys to girls in a class is 1:4" means that you can arrange the class into groups of size 5, each consisting of 1 boy and 4 girls. Thus there are 4 girls per group, that is the fraction of girls is  4/5. Finally write this as a percentage. Now try the other problems. Penny Go to Math Central