 Quandaries and Queries Help!  My name is GiGi Page.  I believe my question could fall into either the middle or secondary level.  I am not a teacher or student-just someone who has forgotten how to calculate some basic percentages.  My question is: What formula would I use to calculate the following:  What percentage of 6 billion is 40 million?  Any information will be greatly appreciated.  Thank you!  GiGi Hi GiGi, You have done much of the work by asking the question is such a precise way What percentage of 6 billion is 40 million?  There is a straightforward method that I use to change this into an algebraic expression which I can then solve. What is the unknown quantity. In algebra we usually give it a symbol like x or y. percent is "per one humdred", that is divided by 100. "of" is multiplication, like "half of 6 is 3". "is" is the verb. Think of some mathematical formula and read it to yourself. The verb is the equal sign. Thus you expression What percentage of 6 billion is 40 million?  becomes  x/100 6,000,000,000 = 40,000,000 To solve this equation first multiply both sides br 100. The equation becomes x 6,000,000,000 = 4,000,000,000 Nuw divide both sides by 6,000,000,000 to get x = 4,000,000,000/6,000,000,000 = 4/6 = 0.667 Thus 40 millioin is 0.667 percent of 6 billion. Penny Go to Math Central