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Big Ideas Math: Modeling Real Life, Grade 7

BI

Big Ideas Math: Modeling Real Life, Grade 7 View details

Practice Test

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Exercise 9 Page 42

To add or subtract fractions, they need to have the same denominator.

- 31/18

When adding or subtracting fractions, they should have the same denominator. In this exercise, we have two fractions with different denominators. - 4/9 + (-23/18)Since 18 is a multiple of 9, we can multiply both the numerator and denominator of - 49 by 2 to create a common denominator.

- 4/9+(- 23/18)

a/b=a * 2/b * 2

- 4 * 2/9 * 2+(- 23/18)

Multiply

-8/18+(- 23/18)

Now that we have a common denominator, we can proceed to simplifying the expression.

-8/18+(- 23/18)

a+(- b)=a-b

-8/18-23/18

MoveNegFracToNum

Put minus sign in numerator

- 8/18-23/18

Subtract fractions

-8-23/18

Subtract term

-31/18

MoveNegNumToFrac

Put minus sign in front of fraction

-31/18

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