Core Connections: Course 2
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2. Section 7.2
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Exercise 103 Page 422

Practice makes perfect
We want to find the common denominator to to simplify the expression. 3/4-1/3+(- 5/24) In this exercise, we have three fractions with different denominators. We can find a common denominator by finding the least common multiple (LCM) of the denominators. Since 24 is a multiple of both 4 and 3, we can start by multiplying both the numerator and denominator of 34 by 6 and both the numerator and denominator of 13 by 8 to create a common denominator.
3/4-1/3+(- 5/24)
3* 6/4* 6-1/3+(- 5/24)
3* 6/4* 6-1* 8/3* 8+(- 5/24)
18/24-8/24+(- 5/24)
Now that we have a common denominator, we can proceed to simplifying the expression.
18/24-8/24+(- 5/24)
18/24-8/24- 5/24
18-8-5/24
5/24
When dividing real numbers, the quotient will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case both numbers are positive, so the quotient will be positive.
10/12Ă· 1/4
10/12* 4/1
10* 4/12* 1
40/12
10/3
3 13
When multiplying real numbers, the product will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case both numbers are positive, so the product will be positive. Now, we can start by rewriting each mixed number as a fraction.
3 12* 1 38
7/2* 11/8
7* 11/2* 8
77/16
4 1316
When dividing real numbers, the quotient will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case one number is negative and one number is positive, so the quotient will be negative.
- 20/7Ă· 1/3
- 20/7* 3/1
- 20* 3/7* 1
- 60/7
- 8 47
When multiplying real numbers, the product will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case both numbers are negative, so the product will be negative.
- 8/25* (- 15/32)
8/25* 15/32
8* 15/25* 32
120/800
15/100
0.15
When dividing real numbers, the quotient will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case one number is negative and one number is positive, so the quotient will be negative.
9/4Ă· (- 2/3)
9/4* (- 3/2)
- 9/4* 3/2
- 9* 3/4* 2
- 27/8
- 3 38
- 3.375
We want to find the common denominator to to simplify the expression. 8/21+(- 3/7) In this case, we have two fractions with different denominators. Since 24 is a multiple of both 7, we can start by multiplying both the numerator and denominator of - 37 by 3 to create a common denominator.
8/21+(- 3/7)
8/21+(- 3* 3/7* 3)
8/21+(- 9/21)
Now that we have a common denominator, we can proceed to simplifying the expression.
8/21+(- 9/21)
8/21- 9/21
8-9/21
- 1/21
- 1/21
When multiplying real numbers, the product will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) In our case two numbers are positive and one number is negative. This means that our product will be negative.
7/4* (- 2/5)* 3/5
- 7/4* 2/5* 3/5
- 7* 2* 3/4* 5* 5
- 42/100
- 0.42