rounding is based off of the digit following the place we are rounding to
there are several possibilities for a number when we are "reverse rounding"
the original value could have been
3.73... and was rounded up
or
it could have been 3.74 but rounded down
all we do is identify the range of possible numbers and pick one as our answer
the lowest possible value would be 3.735...
the highest possible value would be 3.744...
so just pick any number falling within that range
