Åk 6–9
 
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4.1 Rounding Decimals

How much does 43.6 liters of gasoline (petrol) cost if the prise per liter is 10.97 kr?

The calculation is 43.6 · 10.7 which gives the answer  478.292 kr.

You can’t pay exactly 478.29 kr and you need therefore, to round off. Here rounding off the answer to 478.50 kr or 478 kr and 50 öre.  Because we don’t have tenths of öre, or one öre or ten öres, we round the answer to the nearest 50 öre or 0.5 kr.


Foto: Fredrik Enander

We will now look at two examples for how you can think about rounding.


Example A

Round the following number to one decimal (tenths).



Example B

Round 3.8501 to one decimal, in other words tenths. We then see that 3.8501 is closer to 3.9 then 3.8. So we round the number to 3.9.