Transcript Comparing and Ordering Fractions - Mendenhall-Jr-PLC

PowerPoint created by
Parsheena Berch
Resource: JBHM material
Pictures: Google Images
Comparing
and Ordering
Fractions
Word of the Day:
• Biography- a written history of a person’s life.
Bell Ringer:
Page 47 in JBHM binder (DOK 3)
Focus/Introduction:
• Friday, we began talking about fractions and the
need for them.
• What is a proper fraction?
• What is an improper fraction?
• What is a mixed number?
• How do you change an improper fraction to a
mixed number and vice versa.
• Today, we will be comparing and ordering
fractions
Guided Practice: (DOK 1)
• Comparing and Ordering Fractions
• Sometimes we have fractions that we need to
compare and order. This can be a little tricky,
especially if the fractions are not some of our
benchmark fractions or common fractions that
we use every day.
• Remember the comparison symbols > (greater
than), < (less than), and = (equal to).
• These will be used to compare fractions just as
they were to compare whole numbers and
decimals.
• In the cookie example, it can be noted that the
fraction with the larger denominator actually
represents the smaller part of the whole or
fraction. This comparison of the two pieces from
our cookie example can be expressed using
mathematical terms and symbols. Show them
that 1/16 is less than 1/8.
Exploring Fractions on a
Number Line
Comparing Fractions
• It is quite simple to compare fractions when
the denominator is the same. These are called
like fractions. To compare them, simply
compare the numerators.
•
3
5
4
is less than
5
• When comparing fractions with unlike
denominators, there is more involved. Often,
pictures are helpful to compare fractions.
• Draw a rectangle and shade in one-half. Draw
another rectangle and shade in one-third.
• This strategy can often be deceiving as it is
difficult to draw pictures that accurately
represent fractional parts.
• Also, it gets quite difficult when working with
fractions involving higher numbers like 21/43.
• There is another strategy that will always work
and is quite simple. It will be referred to as
criss-cross.
Strategy 1: Criss-cross
2
3
3
4
• This tells us which one is greater than (>) or less
than (<). To do this, multiply the numerator in the
first fraction by the denominator in the second
fraction (2 x 4). Write the product above or below
the first fraction. Then multiply the numerator in
the second fraction by the denominator of the first
fraction (3 x 3). Write the product above or below
the second fraction. Compare the products (8 and
9). The result is the answer to comparing the
fractions.
Compare:
2
5
4
7
Compare:
1
3
7
9
Compare:
3
4
5
6
Ordering Fractions
• Sometimes we are given more than two
fractions to order from least to greatest or
vice versa. When given this challenge, we can
try a little math magic to make it fun and easy!
2
3
1
4
1
2
• Multiply the 1st Numerator x 2nd Denominator x 3rd
Denominator
2 x 4 x 2 = 16
This product is assigned to the fraction with the
numerator that was used.
• Multiply the 2nd Numerator x the 3rd Denominator x
1st Denominator
1 x 2 x 3 =6
• Multiply the 3rd Numerator x 1st Denominator x 2nd
Denominator
1 x 3 x 4 = 12
Example:
Independent Practice: (DOK 1
and 2)
• Take Handout #2 from your JBHM binders.
• You will begin to work this in class and will
finish this for homework.
• It is practice on comparing and ordering
fractions.
Closure:
• NO. 1a Compare and order integers, decimals
to the nearest ten-thousandths, like and
unlike fractions, and mixed numbers using <,
>, and =. (DOK 1)
• Remember to finish handout #2 for
homework.