Step by step
The question
Question: A coat costs $120.
It is 30% off.
What is the sale price?
1 Find the discount
Percent means out of 100.
So 30% is 30 divided by 100: 0.3.
The point moves 2 places to the left.
30% = 30 ÷ 100 = 0.3
The discount is 30% of $120.
"Of" means times: 0.3 times $120.
That is $36.
discount = 0.3 × $120 = $36
To multiply decimals: first 3 times 120, as whole numbers.
That is 360.
Then count the decimal places: 1.
So it is 36.0.
3 × 120 = 360
1 decimal places: 36.0
Careful!
The discount is the money we save.
We still pay the rest.
Careful: $36 is what we save, not what we pay
2 Take it off
A discount comes off the price.
$120 minus $36 is $84.
sale price = $120 − $36 = $84
So the sale price is $84.
3 Check
Let's check another way: we pay 100% minus 30%: 70% of the price.
0.7 times $120 is $84.
The same.
So the answer is right!
100% − 30% = 70%: 0.7 × $120 = $84
Let's look back.
First: find the discount.
Then: take it off.
Last: check.
Answer
sale price = $120 − $36 = $84