Rounding makes calculations easier

Rounding makes head calculations easier, such as buying numerous items while shopping

You have three items costing $£3.99$ , $£2.20$ and $£4.85$ . Usually this would be rounded to the nearest pound as:

$£4 + £2 + £5 = £11$

Your bill would be about $£11$ . Your actual bill came to $£11.04$ , so you know the actual bill is about right.