Worked examples
The question
Question: change $250 to euros, when $1 = €0.80.
$1 = €0.80. Change $250 to euros.
1 Write the rate
The rate says: 1 dollar is worth 0.80 euros.
$1 = €0.80
From dollars to euros, we multiply by 0.80.
Going back, we divide by 0.80.
dollars → euros: × 0.80
euros → dollars: ÷ 0.80
2 Multiply by the rate
Each dollar is worth €0.80.
250 dollars are worth 250 times as much.
$250 = 250 × €0.80
250 times 0.80 is €200.
= €200
To multiply decimals: first 250 times 80, as whole numbers.
That is 20000.
Then count the decimal places: 2.
250 × 80 = 20000
2 decimal places: 200
Careful!
Check the direction.
Dollars to euros: we multiply by the rate.
Careful: dollars → euros: × the rate
So $250 is €200.
3 Check
Let's check: change the answer back.
€200 divided by 0.80 is $250.
change it back: €200 ÷ 0.80 = 250
That is what we started with.
So the answer is right!
$250 — what we started with
Let's look back.
First: write the rate.
Then: multiply by the rate.
Last: check.
Answer Careful: dollars → euros: × the rate
▶ Watch it solved
The question
Question: change €60 to dollars, when $1 = €0.80.
$1 = €0.80. Change €60 to dollars.
1 Write the rate
The rate says: 1 dollar is worth 0.80 euros.
$1 = €0.80
From dollars to euros, we multiply by 0.80.
Going back, we divide by 0.80.
dollars → euros: × 0.80
euros → dollars: ÷ 0.80
2 Divide by the rate
Each $1 gives €0.80.
So we find how many €0.80 fit in €60: we divide by 0.80.
€60 = $ 600.80
Careful!
From euros back to dollars goes the other way.
We divide, not multiply.
Careful: not 60 × 0.80 = 48 ✗
60 divided by 0.80 is $75.
= $75
To divide by 0.80, we move the point in both numbers 2 places: 6000 divided by 80.
60 ÷ 0.80 = 6000 ÷ 80 = 75
So €60 is $75.
3 Check
Let's check: change the answer back.
$75 times 0.80 is €60.
change it back: $75 × 0.80 = 60
That is what we started with.
So the answer is right!
€60 — what we started with
Let's look back.
First: write the rate.
Then: divide by the rate.
Last: check.
Answer 60 ÷ 0.80 = 6000 ÷ 80 = 75
▶ Watch it solved
The question
Question: change $65 to euros, when $1 = €0.92.
$1 = €0.92. Change $65 to euros.
1 Write the rate
The rate says: 1 dollar is worth 0.92 euros.
$1 = €0.92
From dollars to euros, we multiply by 0.92.
Going back, we divide by 0.92.
dollars → euros: × 0.92
euros → dollars: ÷ 0.92
2 Multiply by the rate
Each dollar is worth €0.92.
65 dollars are worth 65 times as much.
$65 = 65 × €0.92
65 times 0.92 is €59.80.
= €59.80
To multiply decimals: first 65 times 92, as whole numbers.
That is 5980.
Then count the decimal places: 2.
65 × 92 = 5980
2 decimal places: 59.8
Careful!
Check the direction.
Dollars to euros: we multiply by the rate.
Careful: dollars → euros: × the rate
So $65 is €59.80.
3 Check
Let's check: change the answer back.
€59.80 divided by 0.92 is $65.
change it back: €59.80 ÷ 0.92 = 65
That is what we started with.
So the answer is right!
$65 — what we started with
Let's look back.
First: write the rate.
Then: multiply by the rate.
Last: check.
Answer Careful: dollars → euros: × the rate
▶ Watch it solved
