Money is written to two decimal places
An amount of money is given to decimal places (the smallest coin). A calculator showing for an amount of money means \4.804.5$4.50$ — read the second decimal place as the number of cents/pence.
To convert currency, multiply by the rate
If unit of currency A buys units of currency B, then an amount in A is worth in B. The rate is "how many B you get for one A". Always check which way the rate points before you multiply.
To convert back, divide by the same rate
If A B, then to turn an amount in B back into A you divide: . Multiplying converts one way; dividing converts the other way with the same rate.
Drawn from real examiner reports.
Multiplying when you should divide
Students often multiply by the rate in both directions. If dollar euros, then dollarseuros multiplies by , but eurosdollars divides by . Picture which currency is worth more to sanity-check the size of the answer.
Rounding money to the wrong d.p.
A money answer should be given to decimal places. Writing \344.8$344.83$, or chopping to a whole number, loses accuracy marks. Only round at the end, not partway through.
Rounding the intermediate amount
In a two-step conversion, do not round the middle value. Keep full accuracy through the calculation and round only the final money answer to decimal places; rounding early can shift the last penny.
Adding or averaging two exchange rates
For an A B C conversion you apply the two rates one after another (multiply in turn). Adding them, or averaging them, is wrong — each rate acts on the output of the previous step, not on the original amount.
Misaligning decimals when adding money
Line up the decimal points before adding or subtracting money. Treating as and misaligning the columns gives the wrong total — keep every amount to decimal places.
Two-step conversion: apply each rate in turn
To go ABC, convert A into B first (using the AB rate), then convert that result into C (using the BC rate). Don't round the intermediate amount.
Sanity-check the size of a conversion
Before writing the answer, ask if it should be bigger or smaller. If one unit of currency A is worth more than one unit of B, then an amount in A must give more of B — if your answer came out smaller, you divided when you should have multiplied.
Round money only at the very end
Carry full accuracy through every step and round to decimal places only at the end. Rounding a partway value and then multiplying can push the final penny out.
Money amounts are written to 2 decimal places (the smallest coin). A calculator display of for an amount of money means \4.804.5$4.50$. Read the second decimal place as the cents/pence.
When adding, subtracting and finding change, keep everything to d.p. and only round the final answer.
A calculator shows 4.8 for an amount of money. What is the actual amount?
The exchange rate is USD EUR. Convert US dollars into euros.
