Читать книгу Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online) - Mark Zegarelli - Страница 62

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(a)

(b)

(c)

(d)

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(a) Fifteen is less than , so subtract and attach a negative sign to the result: −7.

(b) Twenty-seven is less than , so subtract and attach a negative sign to the result: .

(c) Eighty-nine is less than , so subtract and attach a negative sign to the result: .

(d) One thousand is less than , so subtract and attach a negative sign to the result: .

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(a) To negate , attach a negative sign:

(b) To negate , attach a negative sign: . Now cancel adjacent negative signs: .

(c) Zero is its own negation.

(d) Add first: , and the negation of .

(e) Subtract first: , and the negation of .

(f) Begin by subtracting: , and the negation of .

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(a) The number is already positive, so the absolute value of .

(b) The number is negative, so the absolute value of .

(c) First, do the addition inside the absolute value bars: , which is positive. The absolute value of .

(d) First, do the subtraction: , which is positive. The absolute value of . You have a negative sign outside the absolute value bars, so negate your answer to get .

(e) Begin by subtracting: , which is negative. The absolute value of .

(f) The absolute value of .

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(a) Start at , up .

(b) Start at , down .

(c) Start at , down .

(d) Start at , up .

(e) Start at , down .

(f) Start at , down .

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(a) 18. Switch around the numbers (with their signs) to turn the problem into subtraction:

(b) −9. Drop the plus sign to turn the problem into subtraction:

(c) −79. Drop the signs, add the numbers, and negate the result:

(d) 7. Turn the problem into subtraction:

(e) −28. Turn the problem into subtraction:

(f) −537. Drop the signs, add the numbers, and negate the result:

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(a) Start at , down .

(b) Start at , up .

(c) Start at , up .

(d) Start at , down .

(e) Start at , down .

(f) Start at , up .

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(a) 43. Cancel the adjacent negative signs to turn the problem into addition:

(b) −66. Drop the signs, add the numbers, and negate the result:

(c) 46. Cancel the adjacent negative signs to turn the problem into addition:

Now switch around the numbers (with their signs) to turn the problem back into subtraction:

(d) −158. Drop the signs, add the numbers, and negate the result:

(e) 124. Cancel the adjacent negative signs to turn the problem into addition:

(f) −71. Cancel the adjacent negative signs to turn the problem into addition:

Now switch around the numbers (with their signs) to turn the problem back into subtraction:

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(a)

(b)

(c)

(d)

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(a)

(b)

(c)

(d)

11 First, drop the signs and multiply:

The numbers have different signs, so the answer is negative: .

12 Drop the signs and multiply:

The numbers have the same sign, so the answer is positive: .

13 Drop the signs and divide (use long division, as I show you in Chapter 2):

The numbers have different signs, so the answer is negative: .

14 135. First, drop the signs and divide:

The numbers have the same sign, so the answer is positive: .

The chapter quiz in the next section tests you on your skills working with negative numbers.