Common fractions and decimals

Topic Notes

In this lesson, we will learn:

  • How to convert between decimals and decimal fractions (tenths and hundredths)
  • How to convert between decimals and unit fractions
  • How to convert between decimals and fraction halves and quarters

Notes:

  • Decimals can be converted into fractions and vice versa
    • Recall that place values are related to their neighbors by a factor of 10

    • Common fractions and decimals

  • Decimals can be easily converted into decimal fractions
    • Decimal fractions have denominators that are powers of 10
    • Decimal tenths are fractions out of 10
      • Ex. 0.3 = 310\large \frac{3}{10} ; 3 tenths = 3 out of 10 Common fractions and decimals
    • Decimal hundredths are fractions out of 100
      • Ex. 0.22 = 22100\large \frac{22}{100} ; 22 hundredths = 22 out of 100 Common fractions and decimals
    • Decimal hundredths can also be expressed as a sum of fractions, because of equivalent decimals (i.e. 0.2 = 0.20)
      • 0.22 = 22100\large \frac{22}{100} = 20100\large \frac{20}{100} + 2100\large \frac{2}{100} = 210\large \frac{2}{10} + 2100\large \frac{2}{100}

  • Two type of common fractions have a denominator of 2 or 4

Type

Fraction

Decimal Value

"half"

12\frac{1}{2}


= 50100\frac{50}{100} = 510\frac{5}{10}

0.5

"quarter"

14\frac{1}{4}


= 25100\frac{25}{100}

0.25