Step by step
The question
Question: $5 for 2 and 1/2 pounds: how much is that per pound?
A unit rate says how much for 1 pound.
Per pound means: divide by the pounds.
1 Write the rate
Dollars divided by pounds: 5 ÷ 2 and 1/2.
Careful!
Not the other way round.
That would be pounds per dollar.
2 Divide
2 and 1/2 is a mixed number.
Each whole one is 2/2.
So we do 2 times 2, plus 1.
The bottom stays 2.
2 times 2 plus 1 is 5.
So it is 5/2.
Dividing by a fraction is the same as times its flip.
Keep the first number.
Change divide to times.
Turn the second fraction upside down.
So 5/2 becomes 2/5, and divide becomes times.
Before we multiply, we make the numbers smaller.
5 on top and 5 at the bottom both divide by 5.
A top and a bottom divided by the same number: the answer stays the same.
So we multiply smaller numbers.
1 times 2 is 2.
So the unit rate is $2 per pound.
3 Check
Let's check: $2 per pound, for 2 and 1/2 pounds.
2 times 5/2 is 5.
That is the price we started with.
So the answer is right!
Let's look back.
First: write the rate.
Then: divide.
Last: check.