Percent problems are not nearly as scary as they appear, if you remember this neat trick:

• Draw a cross like so:

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• In the upper left, write PORTION. In the bottom left write WHOLE. In the top right, write PERCENT and in the bottom right, write 100. Whatever your problem is, you will leave blank the unknown, and fill in the other four parts.  For example, let’s suppose your problem is:  Find 10% of 50.  Since we know the 10% part, we put 10 in the percent corner. Since the whole number in our problem is 50, we put that in the corner marked whole.  You always put 100 underneath the percent, so we leave it as is, which leaves only the top left corner blank. This is where we’ll put our answer.Now simply multiply the two corner numbers that are NOT 100.  In this case, it’s 10 X 50. That gives us 500. Now multiply this by the remaining corner, or 100, to get a final answer of 5.  5 is the number that goes in the upper-left corner, and is your final solution.
• Another hint to remember: Percents are the same thing as hundredths in decimals.  So .45 is the same as 45 hundredths or 45 percent.

Percents are simply a specific type of decimals, so it should be no surprise that converting between the two is actually fairly simple.  Here are a few tricks and shortcuts to keep in mind:

• Remember that percent literally means “per 100” or “for every 100.” So when you speak of 30% you’re saying 30 for every 100 or the fraction 30/100.  In basic math, you learned that fractions that have 10 or 100 as the denominator can easily be turned into a decimal.  30/100 is thirty hundredths, or expressed as a decimal, .30.
• Another way to look at it: To convert a percent to a decimal, simply divide the number by 100.  So for instance, if the percent is 47%, divide 47 by 100. The result will be .47. Get rid of the % mark and you’re done.
• Remember that the easiest way of dividing by 100 is by moving your decimal two spots to the left.