If points $C, D$, and $E$ are on a line and $C D=20$ and $C E=32$, what are the possible values of $D E$ ?

Step 1 ：Given that points $C, D$, and $E$ are on a line, with $C D=20$ and $C E=32$.

Step 2 ：There are two possible scenarios: 1. D is between C and E. In this case, $D E = C E - C D$. 2. E is between C and D. In this case, $D E = C D - C E$.

Step 3 ：Calculate the values of $D E$ for both scenarios.

Step 4 ：For the first scenario, $D E = C E - C D = 32 - 20 = 12$.

Step 5 ：For the second scenario, $D E = C D - C E = 20 - 32 = -12$.

Step 6 ：Since distance cannot be negative, the result of the second scenario is not possible.

Step 7 ：Thus, the only possible value for $D E$ is 12.

Step 8 ：Final Answer: \(\boxed{12}\)