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Topic: Fractions
Grade Level: 2-3
Objectives:
Broad:
By performing this activity, students will become familiar with
fractions, and have a meaningful experience to relate them to.
It is hoped that students will become more comfortable with using
fractions and have a better understanding of them.
Narrow:
Students will be able to write a fraction to describe what part
of a region is
shaded. They will also be able to name the numerator and denominator
in a
fraction. Finally, students will be able to identify equal fractions.
The Lesson:
Anticipatory Set:
Imagine that you had a pizza and you wanted to share it with 7
of your friends. How would you divide that pizza up so that each
of you received an equal amount? Tell students that through this
activity they will learn how to divide something into equal parts
by learning about fractions.
Activity For Concept Development:
Day 1:
Give each student a piece of plain white paper and request that
they fold it in half. Now explain that you have divided a whole
piece of paper into two equal parts and that a fraction is simply
a part of a whole. Ask the students to color in one of the two
equal parts, and have one student write ½ on the board to
show that one out of the two equal parts is now shaded.
Now is a good time to introduce the terms numerator and denominator.
Explain the numerator to be the number of parts that are shaded
and the denominator is the total number of equal parts. Students
may remember the association better when it is explained that
down and denominator both start with D.
After you have given this instruction, perform the same activity
with pieces of paper to describe fractions such as ¼, ¾,
18, 23, etc. Each
time this is done, have students write the fraction on the board
and identify the numerator and denominator.
Day 2 (or later in day 1):
To teach equivalent fractions, have students take out the paper
they had folded in half to demonstrate the fraction ½. Have
them fold it again to divide the paper into fourths. Ask them
to unfold the paper and describe what they notice. If students
do not catch on, explain to them that they have divided the paper
into fourths and that 24 of the paper is
shaded and that this is equal to ½. Another way to do this
is to ask what fraction is shaded and students should respond
that 24 and ½ are both shaded. Since
the amount of shading has not changed, this means that ½
is equal to 24. Have students fold the same
paper in half again to demonstrate that ½ is equal to 24
which is equal to 48. Follow this up with
other equivalent fractions such as 23 is
equal to 46.
Practice:
Ask students to continue exploring by folding papers and trying
to come up with as many different equivalent fractions as they
can. This part could be made into a game to increase motivation,
with a reward for the winner with the most equivalent fractions.
Also request that students identify the numerator and denominator
in their examples.
Closure:
To wrap up this lesson, return to the pizza question presented
in the anticipatory set. Question students on what a solution
could be for dividing up the pizza to give to 8 people. Most likely,
students will realize that the pizza should be cut in half, then
cut in half a second and a third time to divide the pizza into
8 equal parts. You may need to lead students into finding this
solution. Another way to make this even more meaningful is to
give students round pieces of paper and have them fold it to divide
it into 8 equal parts.
Materials:
Teacher:
Plain white paper, perhaps some cut in circles, chalkboard, and
chalk.
Students:
Markers.
Bibliography:
* Lofties, Elizabeth. "CECmath.39." Big Sky Telegraph
Math Lesson Plans. gopher://bvsd.k12.co.us:70/00/Educational_Resources/Lesson_Plans/Big%20Sky/
math/CECmath.39 (24, Sept. 1996).
Reys, R. E., Suydam, M. N., & Lindquist, M. M. (1995). Helping
children learn mathematics (4th ed.). Needham Heights,
MA: Allyn and Bacon.
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