Hey there! :D
Since Carol has 100 stamps, the percentages are like whole numbers.
24%= 24 stamps
22%= 22 stamps
25%= 25 stamps
29%= 29 stamps
This is only because she has 100, and the percentages are from 100. If it was 50, it would be much different. You would multiply .25 by 50 for the number of stamps. It was nice that it was 100.
So, now we just find Italy and England and subtract them.
25-22= 3
3 stamps. <== the answer
I hope this helps!
~kaikers