Introduction to Fractions

Objectives

Students will be able to: o write fractions to describe portions o name the numerator and denominator of a fraction

Key Terms

a small portion or part forming a piece of a whole Fraction a small portion or part forming a piece of a whole Ex. 1 4

Numerator the number of portions or parts of the whole, the top number in a fraction Ex. 1 4 numerator

Denominator the total number of portions or parts that make the whole, the bottom number in a fraction Ex. 1 4 denominator

Radical The dividing line that separates the numerator from the denominator, can be read as “…out of…” Ex. 1 4 radical

Who wants pizza?

You’re having a birthday party…

…and your mom made a pizza for everyone to eat.

Including yourself, there are eight people to share the pizza.

How should you cut it so that everyone gets an equal slice?

You can cut it down the middle, but that would only be enough slices for two people.

You can cut the two slices down the middle again, but that would only be enough for four people.

You have an idea! What if you cut those four slices down the middle again? That would be enough. Right?

Let’s see…

One and two…

Three and four…

Five and six…

Seven and eight!

If we cut one pizza…

…into eight slices…

…there will be enough…

…for everyone!!!

In math, we call each slice a fraction of the whole pizza.

…and since we cut one pizza…

…into eight slices…

…each slice could be viewed as… 1

…each slice could be viewed as… 1 …out of… 8

…each slice could be viewed as… …slices, or one eighth of the pizza. 1 …out of… 8 …slices, or one eighth of the pizza.

You’ve just made your first fraction!

Fractions can be really easy Fractions can be really easy. You just have to remember that the number of portions is your numerator, the number on top of the radical. …and the total number of portions that make the whole is your denominator, the number on bottom.

Let’s practice!

What fraction of the pentagon is blue?

Nine portions…

Nine portions out of the ten total portions are blue, so…

Nine portions out of the ten total portions are blue, so… 9 out of 10 …or…

Nine portions out of the ten total portions are blue, so… 9 out of 10 …or… 9 10 nine tenths

9 10 That would make 9, the portion and number on top, our numerator… …and ten, the whole and number on bottom, our denominator.

Let’s try another!

What fraction of the pentagon is red?

What fraction of the pentagon is red?

Three portions…

Three portions out of the five total portions are red, so…

Three portions out of the five total portions are red, so… 3 out of 5 …or…

Three portions out of the five total portions are red, so… 3 out of 5 …or… 3 5 three fifths

Which number is the numerator? 3 5

Which number is the numerator? 3 5

Which number is the numerator? 3 5 So what does that make the five?

Which number is the numerator? 3 5 So what does that make the five? the denominator

…but let’s see how good you The Pizza Fraction Game!!! I think you’ve got it! …but let’s see how good you really are by playing The Pizza Fraction Game!!!