Percents and Populations

I wanted to try some math with this activity.The students at my school do poorly in multiplication and specially decimals. I found this activity and wanted to try it with them. The students have a case and they had to come up with an answer to the problem. I only had six students and I split them up in two groups. Question they had to do. Suppose a doctor is treating a group of people who have the disease hemophilia.The group has 400 people. About how many individuals would you expect to have hemophilia A?
Team A (hemophilia A)
1)Write percent as a decimal.
80%= .80 (some students can not change percents to decimals)
2)Multiply the decimal number by the total population.
.80 X 400= 320.00 (if what they were suppose to get)
3) Be sure the answer has the same number of decimals place.
Team B (hemophilia B)
1)Write percent as a decimal.
12%= .12 (some students can not change percents to decimals)
2)Multiply the decimal number by the total population.
.12 X 400= 48.0 (if what they were suppose to get)
3) Be sure the answer has the same number of decimals place
(The Challenge: The part that made them think)
Write a fraction in simplest terms equal to each percentage: 80, 30, 12, 3.
Question: When you multiply these fractions by 400, do you get the same or different results as when you multiply 400 by the percentages? Explain why the results may be different.