5.3 and 5.4 operations with fractions
DESCRIPTION
5.3 and 5.4: Operations with Fractions.TRANSCRIPT
The 44th President of the United States of America.
Chapter 5Section 3: Adding and Subtracting Fractions.
November 5th, 2008
The Day After Election Day.
Same Denominator, Easy Cheesy
When the DENOMINATOR is the same
just add or subtract
the NUMERATOR.
Like These
• 3/7 + 1/7 =
• 2/k + 3/k =
• 7/10 – 3/10 =
• (11/y) + (-5/y) =
From Yesterday
To add or subtract fractions with unlike denominators:
Write the fractions with a common denominator (LCM).
A/B + C/D = ?If you can’t find the LCM, make up one.
Simplify Each: Difference or Sum
-7/8 + ¾ =
1/8 – 5x/6 =
3/7 + 2/m =
Adding/Subtracting/Mixed Numbers
Before Adding/Subtracting Mixed Numbers, Make Them Into Improper Fractions!
5 ¾ + 7/8 =
25 1/3 + 3 5/6 =
2 3/8 + 7/16 =
Chapter 5Section 4: Multiplying and
Dividing Fractions
Multiplying Rational Numbers
Rational Numbers are Numbers that can be EXPRESSED as a Fraction, or Ratio!
Multiply the Numerators and Denominators
(2/5)(1/3) =
(-5/6)(2/3) =
Simplify Before You Multiply
When a Numerator AND Denominator have COMMON FACTORS, you can Simplify
before Multiplying.
(9/15)(5/9) = (y/4)(8/11)=
Multiply and Simplify
(-5/14)(21/25) =
(2x/9)(3/4) =
(2/3)(6/7) =
Multiplying Mixed Numbers?
Convert to an
IMPORPER FRACTION,
then SIMPLIFY.
Word Problem
• Central Park in New York City is a rectangle. It is approximately 2 ½ miles long and ½ miles wide. What is the area of Central Park? (Formula: A = LW)
Find Each Product
• (3 ¾)(2/5) =
• (2/3)(1 2/7) =
• (-2 5/6)(1 3/5) =
Dividing Rational Numbers
3 ½ = Is the same as saying:
“How many haves are in three wholes?”
Reciprocal
2/1 (or 2) and ½ are RECIPROCALS.
Every number can be written as RATIONAL number, which
means it has a RECIPROCAL.
Reciprocal
The PRODUCT of two RECIPROCALS is 1.
Dividing Fractions
To Divide Fractions…
1) Make the SECOND fraction into it’s RECIPROCAL.
2) Change the Division operation INTO a MULTIPLICATION operation.
3) Then MULTIPLY.
4) Don’t forget to Simplify If Possible!
Divide These Fractions
• (2/9) (2/5) =
• (x/3) / (x/4) =
• (-1/4) (1/2) =
Divide This!
• (5x/9) / (10x/27) =
• (-1 3/5) (-1 1/5) =
• (12 ½) / (1 2/3) =
Assignment #34
Page 238: 21-35 Odd.
Page 243: 19-49 Odd.