Expanded Fractions and Decimals
Task
Complete the table.
Fraction | Expanded Fraction Form | Expanded Decimal Form | Decimal |
$43 \frac{65}{100}$ | $40 + 3 + \frac{6}{10} + \frac{5}{100} $ | $40 + 3 + 0.6 + 0.05$ | $43.65$ |
$21 \frac{90}{100}$ | |||
$40 \frac{76}{100}$ | |||
$7 \frac{82}{100}$ | |||
$18 \frac{3}{100}$ |
IM Commentary
The purpose of this task is for students to show they understand the connection between fraction and decimal notation by writing the same numbers both ways. Comparing and contrasting the two solutions shown below shows why decimal notation can be confusing. The first solution shows the briefest way to represent each number, and the second solution makes all the zeros explicit.
Solutions
Solution: Supressing unnecessary zeros
Fraction | Expanded Fraction Form | Expanded Decimal Form | Decimal |
$43 \frac{65}{100}$ | $40 + 3 + \frac{6}{10} + \frac{5}{100} $ | $40 + 3 + 0.6 + 0.05$ | $43.65$ |
$21 \frac{90}{100}$ | $20 + 1 + \frac{9}{10} $ | $20 + 1 + 0.9 $ | $21.9$ |
$40 \frac{76}{100}$ | $40 + \frac{7}{10} + \frac{6}{100} $ | $40 + 0.7 + 0.06$ | $40.76$ |
$7 \frac{82}{100}$ | $7 + \frac{8}{10} + \frac{2}{100} $ | $7 + 0.8 + 0.02$ | $\hskip 6pt 7.82$ |
$18 \frac{3}{100}$ | $10 + 8 + \frac{3}{100} $ | $10 + 8 + 0.03$ | $18.03$ |
Solution: Keeping all zeros
Fraction | Expanded Fraction Form | Expanded Decimal Form | Decimal |
$43 \frac{65}{100}$ | $40 + 3 + \frac{6}{10} + \frac{5}{100} $ | $40 + 3 + 0.6 + 0.05$ | $43.65$ |
$21 \frac{90}{100}$ | $20 + 1 + \frac{9}{10} + \frac{0}{100} $ | $20 + 1 + 0.9 + 0.00$ | $21.90$ |
$40 \frac{76}{100}$ | $40 + 0 + \frac{7}{10} + \frac{6}{100} $ | $40 + 0 + 0.7 + 0.06$ | $40.76$ |
$7 \frac{82}{100}$ | $\hskip 6pt 0 + 7 + \frac{8}{10} + \frac{2}{100} $ | $\hskip 6pt 0 + 7 + 0.8 + 0.02$ | $\hskip 6pt 7.82$ |
$18 \frac{3}{100}$ | $10 + 8 + \frac{0}{10} + \frac{3}{100} $ | $10 + 8 + 0.0 + 0.03$ | $18.03$ |
Expanded Fractions and Decimals
Complete the table.
Fraction | Expanded Fraction Form | Expanded Decimal Form | Decimal |
$43 \frac{65}{100}$ | $40 + 3 + \frac{6}{10} + \frac{5}{100} $ | $40 + 3 + 0.6 + 0.05$ | $43.65$ |
$21 \frac{90}{100}$ | |||
$40 \frac{76}{100}$ | |||
$7 \frac{82}{100}$ | |||
$18 \frac{3}{100}$ |