A code owns a half-open voltage interval. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A code starts at its left edge
Code 5 starts at 5 volts when the LSB is 1 volt.
vlow=0+5⋅1V=5V
The right edge is excluded
The interval is 5 to 6 volts, with the right edge left open.