 # 4.5 Changing a Decimal or Fraction to a Percent 1 Converting a Decimal to a Percent To convert from a decimal to a percent, we will now multiply by “100”.

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4.5 Changing a Decimal or Fraction to a Percent 1 Converting a Decimal to a Percent To convert from a decimal to a percent, we will now multiply by “100”. This is simply done by moving decimal point two places to the right. Previously, we learned how to convert a percent to a decimal; move the decimal point 2 places to the left. The reason; we were dividing by 100 because percent means out of 100. Procedure:To convert a decimal to a percent: Step 1:Rewrite by inserting the percent symbol (%). Move the decimal point two places to the right. Insert trailing zeros if necessary. Example 1. Convert the following decimals to percents. a. 0.25b. 0.7c. 0.0775d. 4.3 Solution: Your Turn Problem #1 Convert the following decimals to percents. a.0.38 b.2 c.0.052 Hint: Decimal to Percent: (D  P): Move decimal to the right. (DP is alphabetical) Percent to Decimal: (P  D): Move decimal to the left. (PD is not alphabetical) a. 25%b. 70%c. 7.75%d. 430% Answers: a.38% b.200% c.5.2%

4.5 Changing a Decimal or Fraction to a Percent 2 Converting a Fraction to a Percent Example 2. Convert the following fractions to percents. Answers: a.40% b.87.5% Procedure: Converting a Fraction to a Percent Step 1. Convert the fraction to a decimal (divide denominator into numerator). Step 2. Convert the decimal to a percent by moving the decimal point 2 places to the right and adding the percent symbol. 1 st, convert to a decimal 2 nd, convert to a percent. 1 st, convert to a decimal 2 nd, convert to a percent. Your Turn Problem #2 Convert the following fractions to percents.

4.5 Changing a Decimal or Fraction to a Percent 3 Example 3. Convert the following fractions to percents. Answers: a.220% b.418.75% 1 st, convert to a decimal 2 nd, convert to a percent. 1 st, convert to a decimal 2 nd, convert to a percent. Your Turn Problem #3 Convert the following mixed numbers to percents. Converting a Mixed Number to a Percent Procedure: Converting a Mixed Number to a Percent Step 1. Convert the fraction part to a decimal (divide denominator into numerator). Write the whole number in front of the decimal. Step 2. Convert to a percent by moving the decimal point 2 places to the right and adding the percent symbol.

4.5 Changing a Decimal or Fraction to a Percent 4 Converting a Fraction to a Percent with a Fractional remainder. Example 4. Convert the following fractions to percents with a fractional remainder. Procedure: Converting a Fraction to a Percent with a Fractional Remainder Step 1. Convert the fraction to a decimal. Only obtain 2 places in the quotient. Step 2. Convert the decimal to a percent by moving the decimal point 2 places to the right, write the remainder over the divisor, and adding the percent symbol. (Do not write a decimal between the whole number and the fractional remainder. 1 st, convert to a decimal 2 nd, convert to a percent. 1 st, convert to a decimal 2 nd, convert to a percent. Your Turn Problem #4 Convert the following fractions to percents with a fractional remainder. Answers:

4.5 Changing a Decimal or Fraction to a Percent 5 Converting a Fraction to a Percent Rounding to a Specified Place Value. When converting a decimal to a percent, we move the decimal point to the right 2 places. Example: 0.7258 = 72.58% Notice the tenths place in the percent is the thousandths place in the original problem. If we are asked to round to a specified place value, we look at the digit to the right which determines whether to round up or round down. We must also consider the place values will move two units to the right. How many places when dividing? If rounding to the tenths place, we need to go 1 place value past the new tenths place. That’s 4 places past the original decimal point. The example above would be 72.6% rounded to the nearest tenth. It follows that if we are rounding to the hundredths place, we would to 5 places past the decimal point. etc. Next Slide

4.5 Changing a Decimal or Fraction to a Percent 6 Example 5. Convert the following fractions to percents. Round to the nearest tenth of a percent. 1 st, convert to a decimal (4 places) 2 nd, convert to a percent, round to the tenths. Your Turn Problem #5 Convert the following percents to fractions. 1 st, convert to a decimal (4 places) 2 nd, convert to a percent, round to the tenths. Answers: The End

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