Aims: Students will be able to describe different kinds of fractions.
Learning objectives for this lesson:
Students will be able to:
- determine the part number and proportion of determine the part of a whole number
- understand that the denominator must not be equal zero
- call the numerator the denominator of fraction
- distinguish proper and improper fractions
- apply the translation’s algorithm of fractions from one kind of form to another
- compare common fractions with the same numerators and denominators
- evaluate their work in the classroom
Aids:
a) Visual aids: flipchart
b) Technical means: active board
Plan
I. Introduction
a) Greeting students
b) Introducing.
c) Motivation:
1) What are the parts of the circle? What are these numbers? How are they written? (Expected answers: 1/2, 1/3, 1/4)
So, our theme is “Fractions”. We’ll study them right now…
II. An explanation of the new >topic
We are going to consider the following questions:
- What is a fraction?
- Fraction Examples.
- Fraction Parts: Numerator, Denominator, Vinculum.
- Fraction Types: Proper Fractions, Improper Fractions, Mixed Fractions.
- Comparing Fractions
WHAT IS A FRACTION
A fraction is a part of a whole.
When an object is divided into a number of equal parts then each part is called a fraction.
There are different ways of writing a fraction. For example, two fifths of an object can be written as
- a common fraction 2/5;
- a decimal 0,4;
The top number of the fraction is called the numerator. The bottom number is called the denominator.
2 numerator says how many parts are in the fraction
vinculum = "divide by"
5 denominator says how many equal parts in the whole object.
Always remember: denominator can never be equal 0. Why?
(Expected answers: Because you can not divide by 0.)
FRACTION EXAMPLES
Example 1:
We divide a chocolate bar into 5 equal parts. Each part is 1/5 of the whole bar. We
read 1/5 as one fifth. The whole bar has 5 fifth parts. We write it1/5.
Example 2:
We have a box of gingerbread men. There are 5 men in the box. Each man is 1/5 of the box contents. The whole box has 5 fifth parts. We write it 1/5. Two gingerbread men are pink. Two pink men are 1/5 of the box contents.
Exercise 1.
Now I suggest you to call the following numbers. You need to talk and check each other with your partner then we’ll listen to your answers together.
(Expected answers: 6/10, 3/7, 5/6, 4/8, 2/5, 1/3)
FRACTION TYPES
There are 3 different types of fractions:
- Proper Fractions
Proper fractions have the nominator part smaller than the denominator part,
for example1/2, 2/5 or 19/20.
- Improper Fractions
An improper fraction has a numerator that is bigger than its denominator, for example 5/5 or 7/2.
- Mixed Fractions
Mixed fractions have a whole number plus a fraction, for example 2(1/5) or 123(19/20).
An improper fraction can be thought of as another way to write a mixed number. A mixed number can be converted to an improper fraction in three steps:
- Multiply the whole part by the denominator of the fractional part.
- Add the numerator of the fractional part to that product.
- The resulting sum is the numerator of the new (improper) fraction, with the 'new' denominator remaining precisely the same as for the original fractional part of the mixed number.
Similarly, an improper fraction can be converted to a mixed number:
- Divide the numerator by the denominator.
- The quotient (without remainder) becomes the whole part and the remainder becomes the numerator of the fractional part.
- The new denominator is the same as that of the original improper fraction.
Exercise 2.
You need to try to find out the answers for this task.
Rename these improper fractions as mixed numbers:
COMPARING FRACTIONS
You have looked at the flip chart comparing fractions. I’ll propose to draw a conclusion.
(Expected answers: If the numerators of two fractions are the same, the fraction with the smaller denominator is the larger fraction. While comparing two fractions with the same denominators, the larger fraction is the one with the greater numerator.)
EXERCISES
Solve the following problems:
1. Which fraction is bigger than 2/3:
A. 2/5 B. 4/7 C. 2/4 D. 3/4 ____________
2. Tell if the fraction on the left is less or greater than the fraction on the right.
2/3 3/5 16/5 7/3
3. Rename the following mixed numbers as improper fractions:
2(4/5) 1(3/6) 4(5/7) 3(4/5)
Answers: ________ _________ ________ ________
4. Word problem: John and Maria bought a medium pizza that has 8 slices. If John ate 2/4 slices and Maria ate 3/8, who ate more pizza?
III. Conclusion
a) Feedback Which activities did you enjoy most? What else would you like to know?
b) Home work: Give examples for all types of fractions and to compare them.
c) Reflection.