3.1 Doubling an uncertain value

$x = 1 +- 0.1;
calculate 2 * $x;

This yields the result

Result without perturbation: 2 Result with symmetric tails: 2.0011 +- 0.199435 Result with asymmetric tails: 2.0011 (1.80269 to 2.20156)

As expected, the error simply doubles, from 0.1 to 0.2, as the value is doubled.