Interpolation
In the domain of science, a scientist may need to use a computer to calculate a complicated function. However, if that function takes a very long time to compute, it may make her experiments difficult or impossible to run properly. So, she might use interpolation to create a slightly less complicated version of her function, which takes less computational time and energy to run. This interpolated function should achieve the same results as the more complex function, but will make some errors, or lose some detail as compared to the original function. However, the reduced time and cost of running the interpolated function may make this trade-off worthwhile.