Google sheets - Subtraction giving unexpected results

Question

I have the following sheet:

Why does the difference of two cells with the same value (J7 & J8) not equal zero?

Here is an example spreadsheet.

Answer 1

Switching to Format/Number/Scientific on that cell, you can see the leftover value:

These rounding errors are clearly a regular thing. You can use a formula such as =E3-round(E3,2) to see them for any cell:

Clearly, allowing for a small value in the conditional formatting would avoid the problem: