Rounding a price to the nearest pound is the same as rounding a decimal to the closest whole number. If the price is £2.80 you can round up to £3 because the number in the tenths position is 8.

Rule: Either provide the exact fraction or decimal of the probability or ... it should be rounded up to the next higher whole ...

That’s call binary coded decimal or BCD and that has some advantages, too. It is pretty easy to do math on BCD numbers and you don’t get rounding problems. Some CPUs even have specific ...