Float multiplication
$1.4$ and $0.8$ cannot be represented exactly in a IEEE floating point number. 

This means that the actual number stored and operated on is really $1.4+\epsilon$ and $0.8+\epsilon$ where $\epsilon$ is the rounding error and when you multiply those two ends up as $1.12 + 2.2\epsilon+\epsilon^2$.

This rounding error propagation can bite you in the *** at the weirdest times (like making a platform drift slowly upwards enough to allow niche players to shave off a specific button press) and make the results at the end completely wrong if enough operations align to make the error significant enough to matter. One of the major operations to watch out for in this regard is subtraction of nearly equal numbers so the mathematical result becomes close to the error on the inputs.