A Book About Ratios and Rates

This is Chapter 4.
This chapter is about ratios.
This chapter is about proportions.
We use them to solve problems.
The problems are about real life.
This chapter takes six weeks.

What Will We Learn?

We will learn about unit rates.
A unit rate compares two things.
One example: walking speed.
You can walk far in some time.
We can find how fast that is.

We will learn about proportional relationships.
Two things can grow together.
We call this a proportional relationship.

We will learn many ways to show this.
We can use a table.
We can use a graph.
We can use an equation.
We can use pictures.
We can use words.

We will learn to solve problems.
Some problems use percents.
Some problems are about price going up.
This is called markup.
Some problems are about price going down.
This is called markdown.
Some problems are about tax.
Some problems are about tips.

Words We Will Learn

Here are some new words.

Ratio — this compares two amounts.
Rate — this compares two different things.
Unit rate — this compares one thing to just one of another thing.
Proportion — this says two ratios are equal.
Equation — this is a math sentence with an equal sign.
Table — this shows numbers in rows.
Graph — this shows numbers as a picture.
Percent change — this shows how much something goes up or down.

What Do We Already Know?

We already know about fractions.
We already know about decimals.
We already know how to reduce fractions.
We already know about percents.
We learned about ratios before.
We wrote ratios with fractions.
We wrote ratios with colons, like this: 2:3.
We wrote ratios with words too.

We can use pictures to solve ratio problems.
We can use pictures to solve percent problems.

Why Does This Matter?

Ratios and proportions are very important.
We will use them in math for a long time.
Learning this now will help us later.