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Adding & Subtracting Fractions, Mixed Numbers, and Rational Expressions. Preview. When you finish this unit, you will be able to:. Add and subtract fractions with the same denominator Add and subtract signed numbers with the same denominator. Preview.
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Adding & Subtracting Fractions, Mixed Numbers, and Rational Expressions
Preview When you finish this unit, you will be able to: • Add and subtract fractions with the same denominator • Add and subtract signed numbers with the same denominator
Preview When you finish this unit, you will be able to: • Add and subtract rational expressions with the same denominator • Add and subtract fractions with different denominators
? 100 Adding Fractions with the Same Denominator how many .25’s =
10¢ + 10 ¢ = 20 ¢ Fractions/Same Denominator
+ = 3 2 + 5 = Fractions/Same Denominator Whole 6 slices
= + 1 3 4 + = Fractions/Same Denominator Whole5 pieces
numerators add keep deno min ator Fractions/Same Denominator D pieces
+ = Fractions/Same Denominator 5total
+ = Fractions/Same Denominator 7total
? 100 Fractions/Same Denominator Subtracting Fractions with the Same Denominator how many .25’s =
- = Fractions/Same Denominator 7 pieces
An example Fractions/Same Denominator Jack gas gauge reads 7/8 of a tank at the beginning of the day. At 5 PM the gauge reads 1/8 full. How much of a tank-full of gas has he used that day? If he gets 240 miles on a full tank, how far has he driven? Jack gas gauge reads 7/8 of a tank at the beginning of the day. At 5 PM the gauge reads 1/8 full. How much of a tank-full of gas has he used that day? If he gets 240 miles on a full tank, how far has he driven?
7/8 full - start 1/8 full - end 240 miles - full tank 7 8 Full240 mi 1 8 how much of a tank-full? how far has he driven? Fractions/Same Denominator Given: Asked:
Fractions/Same Denominator Asking for the difference between beginning and the the end of the day. Subtract - tankused Gas used is ¾ of 240 mi -
Fractions/Same Denominator Check: Is 180 gal ¾ of 240 gal? OK
subtract numerators keep deno min ator Fractions/Same Denominator Rule:
? 100 Signed numbers with the Same Denominator how many .25’s =
Signed Numbers A flash from the past
Signed Numbers All operations of integer math apply!
4x2 – x + 1 x – 3 - Rational Expressions with the Same Denominator 4 4 4x2 – x + 1 – x + 3 4 6x2 - 1x + 9 = 4
Rational Expressions/Same Denominator Rational Number: Number expressed as a ratio of integers Like Terms:having the same variables, raised to the same powers.5x2 + 2x2 = 7x2 … 5x3 + 2x2 = ?
.05 + .10 = .15 = 15 3 = 100 20 Fractions with Different Denominators
+ = Fractions/Different Denominator + = quarter dollar half dollar
+ = Fractions/Different Denominator + = quarter dollar half dollar
Fractions/Different Denominator + = one quarter dollar two quarter dollars + =
Fractions/Different Denominator + = + =
Fractions/Different Denominator • Upscale fractions without changing value so that they all have the same denominator. • Do the math
Fractions/Different Denominator At the end of the day, Chuck’s Diner has 2 pieces of an apple pie cut into 6 slices and one piece of an equal sized blueberry pie cut into 4 slices left over. How much pie remains? At the end of the day, Chuck’s Diner has 2 pieces of an apple pie cut into 6 slices and one piece of an equal sized blueberry pie cut into 4 slices left over. How much pie remains?
Slices are different sizes for each pie Asked: How much pie remains? Fractions/Different Denominator Given: 2 pieces of 6 slices1 piece of 4 slices
+ Fractions/Different Denominator 2 pieces of 6 slices1 piece of 4 slices Need to represent 6th and 4th as same denominator.
Fractions/Different Denominator Need to represent 6ths and 4ths with same (common) denominator. + 12 pieces
+ + = = Fractions/Different Denominator 12 pieces + =
Fractions/Different Denominator Finding a common denominator
8 6 6 8 To get a common denominator: Multiply numerator and denominator of each term by the denominator of the other(s). Fractions/Different Denominator The easiest way… 6 8
Fractions/Different Denominator The easiest way… 8 6 6 6 8 8
Fractions/Different Denominator Example:
Fractions/Different Denominator Example:
Fractions/Different Denominator Example:
Review We have seen how to: • Add fractions with the same denominator
Review We have seen how to: • Add subtract with the same denominator