Key Concepts

• Name a decimal number.
  1. Name the number to the left of the decimal point.
  2. Write “and” for the decimal point.
  3. Name the “number” part to the right of the decimal point as if it were a whole number.
  4. Name the decimal place of the last digit.
• Write a decimal number from its name.
  1. Look for the word “and”—it locates the decimal point. Place a decimal point under the word “and.” Translate the words before “and” into the whole number and place it to the left of the decimal point.If there is no “and,” write a “0” with a decimal point to its right.
  2. Mark the number of decimal places needed to the right of the decimal point by noting the place value indicated by the last word.
  3. Translate the words after “and” into the number to the right of the decimal point. Write the number in the spaces—putting the final digit in the last place.
  4. Fill in zeros for place holders as needed.
• Convert a decimal number to a fraction or mixed number.
  1. Look at the number to the left of the decimal. If it is zero, the decimal converts to a proper fraction. If it is not zero, the decimal converts to a mixed number. Write the whole number.
  2. Determine the place value of the final digit.
  3. Write the fraction.
     numerator—the ‘numbers’ to the right of the decimal point
     denominator—the place value corresponding to the final digit
  4. Simplify the fraction, if possible.
• Order decimals.
  1. Check to see if both numbers have the same number of decimal places. If not, write zeros at the end of the one with fewer digits to make them match.
  2. Compare the numbers to the right of the decimal point as if they were whole numbers.
  3. Order the numbers using the appropriate inequality sign.
• Round a decimal.
  1. Locate the given place value and mark it with an arrow.
  2. Underline the digit to the right of the given place value.
  3. Is this digit greater than or equal to [latex]5[/latex]? Yes – add [latex]1[/latex] to the digit in the given place value. No – do not change the digit in the given place value
  4. Rewrite the number, removing all digits to the right of the given place value.

Glossary

equivalent decimals

Two decimals are equivalent decimals if they convert to equivalent fractions.