Switch between fractions and decimals without losing precision

The slash creates a fraction

Type $\frac{3}{8}$ on an expression line. In SAT Desmos, the slash opens a stacked fraction. The result is 0.375. The conversion button beside a supported numerical result switches between fraction and decimal display.

Click the same button to switch back. The expression you entered stays unchanged. This is useful when the answer choices use fractions but your result appears as a decimal.

$\displaystyle \frac{3}{8}$

0.375 as a decimal; $\frac{3}{8}$ as a fraction.

$\displaystyle 0.125$

Convert to the fraction $\frac{1}{8}$.

$\displaystyle \frac{2}{3}$

A repeating decimal. Keep $\frac{2}{3}$ for further calculations.

Rounding a repeating decimal changes the number

The decimal 0.6667 is close to $\frac{2}{3}$, but it is not equal to $\frac{2}{3}$. If you enter that rounded decimal and convert it, you are converting the rounded number. Keep the original fraction or expression until the question requires rounding.

Some results, such as $\sqrt{2}$, are irrational: no ratio of two integers equals them. A fraction display cannot turn an irrational value into an exact rational number. Desmos can display a rational approximation, so a fraction display alone does not establish exactness.

Match the form the question requests

For a decimal answer, use the decimal readout and follow the SAT response instructions. For a fractional answer, enter a proper or improper fraction with a slash. Avoid mixed-number notation: use $\frac{5}{2}$ for two and a half.

Before submitting, check the requested quantity and its units. Converting 0.25 to $\frac{1}{4}$ does not convert it to a percentage; 0.25 corresponds to 25%.

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