Conversion involves changing information from one unit of measurement to another. For example, converting euros to pounds sterling (£), distances in kilometres to miles, or weights from pounds to kilograms.
Example one
On a school trip to Spain the entrance fee to a museum for a group of pupils is 64 euros. If the exchange rate is 1.6 euros = £1, what is the group entrance fee in pounds sterling?
Divide the total entrance cost in euros by the numbers of euros equivalent to one pound:
64 ÷ 1.6
This calculation is made easier if you multiply both numbers by 10:
640 ÷ 16 = 40
So the group entrance fee in pounds sterling is £40.
Example two
A teacher led a group of pupils on a camping trip to France. The teacher wanted to arrange a cycle ride of approximately eight miles for the pupils to a local village and back. The signpost at their campsite showed the distance to the following villages:
La Pet 7km
Fouin 6km
Travin 5km
Taking five miles to be equivalent to eight kilometres, which of the three villages should the teacher choose as the destination for the cycle ride?
The return distance from the campsite to La Pet is 2 x 7km = 14km
Convert this to miles by dividing by 8 and multiplying by 5:
14 ÷ 8 x 5 = 8.75 miles
The return distance from the campsite to Fouin is 2 X 6 = 12km
Convert this to miles by dividing by 8 and multiplying by 5:
12 ÷ 8 x 5 = 7.5
The return distance from the campsite to Travin is 2 X 5km = 10km
Convert this to miles by dividing by 8 and multiplying by 5:
10 ÷ 8 x 5 = 6.25 miles
You can also consider that the distance to Travin is less than the distance to Fouin in kilometres. Given that the return distance from the camp to Fouin is 7.5 miles, it is clear that Travin is not the right answer.
You can see that 7.5 miles is closer to 8 miles than 8.75 miles, so Fouin is the village to choose as the destination for the cycle ride.
Example three
For some conversions a formula may be used.
An approximate conversion from kilometres to miles is given by the formula
M = 5/8K
where K represents the number of kilometres and M represents the number of miles. So to convert 12 kilometres into miles, using the formula, you can substitute as follows:
M = 5/8 of 12
M = 60/8 (by multiplying 5 by 12)
M = 7.5 (by dividing by 8)
So 12 kilometres is approximately 7.5 miles.
To convert 60 miles into kilometres substitute into the formula as follows:
60 = 5/8 K
60 x 8 = 5 K (multiply both sides by 8)
480 = 5 K
K = 480 ÷ 5 (divide both sides by 5)
K = 96
So 60 miles is approximately 96 kilometres.