standard_description: Solve word problems involving addition and subtraction of fractions referring to the same whole, including cases of unlike denominators, e.g., by using visual fraction models or equations to represent the problem. Use benchmark fractions and number sense of fractions to estimate mentally and assess the reasonableness of answers. For example, recognize an incorrect result 2/5 + 1/2 = 3/7, by observing that 3/7 < 1/2.
problem_activity: Task
Malia found a "short cut" to find the decimal representation of the fraction $\frac{117}{250}$.  Rather than use long division she noticed that because $250 \times 4 = 1000$,
$$\frac{117}{250} = \frac{117 \times 4}{250 \times 4} = \frac{468}{1000} = 0.468.$$
For which of the following fractions does Malia's strategy work to find the decimal representation?
$$\frac{1}{3}, \frac{3}{4}, -\frac{6}{25}, \frac{18}{7}, \frac{13}{8} \;\; {\rm and} \;\; -\frac{113}{40}.$$
For each one for which the strategy does work, use it to find the decimal representation.
For which denominators can Malia's strategy work?


aligns: no