Calculate $3 for 1 1/2 pounds

Step by step

The question

Question: $3 for 1 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: 3 ÷ 1 and 1/2.

Careful!

Not the other way round.

That would be pounds per dollar.

2 Divide

1 and 1/2 is a mixed number.

Each whole one is 2/2.

So we do 1 times 2, plus 1.

The bottom stays 2.

1 times 2 plus 1 is 3.

So it is 3/2.

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 3/2 becomes 2/3, and divide becomes times.

Before we multiply, we make the numbers smaller.

3 on top and 3 at the bottom both divide by 3.

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 1 and 1/2 pounds.

2 times 3/2 is 3.

That is the price we started with.

So the answer is right!

Let's look back.

First: write the rate.

Then: divide.

Last: check.