Step by step
The question
Question: change €30 to dollars, when €1 = $1.10.
€1 = $1.10. Change €30 to dollars.
1 Write the rate
The rate says: 1 euro is worth 1.10 dollars.
€1 = $1.10
From euros to dollars, we multiply by 1.10.
Going back, we divide by 1.10.
euros → dollars: × 1.10
dollars → euros: ÷ 1.10
2 Multiply by the rate
Each euro is worth $1.10.
30 euros are worth 30 times as much.
€30 = 30 × $1.10
30 times 1.10 is $33.
= $33
To multiply decimals: first 30 times 110, as whole numbers.
That is 3300.
Then count the decimal places: 2.
30 × 110 = 3300
2 decimal places: 33
Careful!
Check the direction.
Euros to dollars: we multiply by the rate.
Careful: euros → dollars: × the rate
So €30 is $33.
3 Check
Let's check: change the answer back.
$33 divided by 1.10 is €30.
change it back: $33 ÷ 1.10 = 30
That is what we started with.
So the answer is right!
€30 — what we started with
Let's look back.
First: write the rate.
Then: multiply by the rate.
Last: check.
Answer
Careful: euros → dollars: × the rate