When we use approximate and simplified models, we greatly increase the retrieval time of items. A great example is when converting Fahrenheit to Celsius.
The normal equation C = ((F-32) * 5)/9 can be greatly simplified by reducing it to C = ((F-32) /2) leading to faster retrieval and calculations. However, the speed of retrieval via the simplified model comes at a cost of accuracy. The new equation has a margin of error of 5 degrees.