Consider a very simple calculation: $231 \times (2.54) ^ 3$, which is the number of cubic cm in a US gallon.

On my phone app calculator I got the exact answer, which is $3785.411784$.

On *Mathematica*, doing the same calculation `231 * (2.54)^3` I got `3785.41`.

Even with `N[231 * 2.54^3, 100]` etc. I got the same (imprecise) answer.

By converting the whole calculation to involve integers `(254^3 * 231 /1000000)` the answer was exact.

The `Precision` function kept indicating `MachinePrecision`, even when using `N[]` with a large number of significant figures.

**How can I increase the precision beyond `MachinePrecision` for trivial calculations like this?**

What if I have more complicated calculations involving exponents or other?

I would want to avoid accumulating loss of precision in each calculation.