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1.1 Real Numbers: Algebra Essentials

Natural, integer, rational, and irrational classifications, order of operations, and the commutative, associative, and distributive properties behind simplifying expressions.

Algebra and Trigonometry 2e, 1.1 Real Numbers: Algebra Essentials

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58 exercises

Writing Integers as Rational Numbers

Write each of the following as a rational number.

  1. ⓐ7
  2. ⓑ0
  3. ⓒ–8
2.5

1.1 Exercise 5

Write each of the following as a rational number.

  1. ⓐ11
  2. ⓑ3
  3. ⓒ–4
2.5

Identifying Rational Numbers

Write each of the following rational numbers as either a terminating or repeating decimal.

  1. ⓐ − 5 7 - \frac{5}{7}
  2. ⓑ 15 5 \frac{15}{5}
  3. ⓒ 13 25 \frac{13}{25}
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1.1 Exercise 7

Write each of the following rational numbers as either a terminating or repeating decimal.

  1. ⓐ 68 17 \frac{68}{17}
  2. ⓑ 8 13 \frac{8}{13}
  3. ⓒ − 17 20 - \frac{17}{20}
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Differentiating Rational and Irrational Numbers

Determine whether each of the following numbers is rational or irrational. If it is rational, determine whether it is a terminating or repeating decimal.

  1. ⓐ 25 \sqrt{25}
  2. ⓑ 33 9 \frac{33}{9}
  3. ⓒ 11 \sqrt{11}
  4. ⓓ 17 34 \frac{17}{34}
  5. ⓔ 0.3033033303333… 0.3033033303333 \ldots
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1.1 Exercise 9

Determine whether each of the following numbers is rational or irrational. If it is rational, determine whether it is a terminating or repeating decimal.

  1. ⓐ 7 77 \frac{7}{77}
  2. ⓑ 81 \sqrt{81}
  3. ⓒ 4.27027002700027… 4.27027002700027 \ldots
  4. ⓓ 91 13 \frac{91}{13}
  5. ⓔ 39 \sqrt{39}
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Classifying Real Numbers

Classify each number as either positive or negative and as either rational or irrational. Does the number lie to the left or the right of 0 on the number line?

  1. ⓐ − 10 3 - \frac{10}{3}
  2. ⓑ 5 \sqrt{5}
  3. ⓒ − 289 - \sqrt{289}
  4. ⓓ −6π −6 \pi
  5. ⓔ 0.615384615384… 0.615384615384 \ldots
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1.1 Exercise 11

Classify each number as either positive or negative and as either rational or irrational. Does the number lie to the left or the right of 0 on the number line?

  1. ⓐ 73 \sqrt{73}
  2. ⓑ −11.411411411… −11.411411411 \ldots
  3. ⓒ 47 19 \frac{47}{19}
  4. ⓓ − 5 2 - \frac{\sqrt{5}}{2}
  5. ⓔ 6.210735 6.210735
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Differentiating the Sets of Numbers

Classify each number as being a natural number (N), whole number (W), integer (I), rational number (Q), and/or irrational number (Q′).

  1. ⓐ 36 \sqrt{36}
  2. ⓑ 8 3 \frac{8}{3}
  3. ⓒ 73 \sqrt{73}
  4. ⓓ −6 −6
  5. ⓔ 3.2121121112… 3.2121121112 \ldots
2.5

1.1 Exercise 13

Classify each number as being a natural number (N), whole number (W), integer (I), rational number (Q), and/or irrational number (Q′).

  1. ⓐ − 35 7 - \frac{35}{7}
  2. ⓑ 0 0
  3. ⓒ 169 \sqrt{169}
  4. ⓓ 24 \sqrt{24}
  5. ⓔ 4.763763763… 4.763763763 \ldots
2.5

Using the Order of Operations

Use the order of operations to evaluate each of the following expressions.

  1. ⓐ ( 3⋅2 ) 2 −4( 6+2 ) \left(3 \cdot 2\right)^{2} - 4 \left(6 + 2\right)
  2. ⓑ 5 2 −4 7 − 11−2 \frac{5^{2} - 4}{7} - \sqrt{11 - 2}
  3. ⓒ 6−| 5−8 |+3( 4−1 ) 6 - \left|5 - 8\right| + 3 \left(4 - 1\right)
  4. ⓓ 14−3⋅2 2⋅5− 3 2 \frac{14 - 3 \cdot 2}{2 \cdot 5 - 3^{2}}
  5. ⓔ 7( 5⋅3 )−2[ ( 6−3 )− 4 2 ]+1 7 \left(5 \cdot 3\right) - 2 \left[\left(6 - 3\right) - 4^{2}\right] + 1
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1.1 Exercise 15

Use the order of operations to evaluate each of the following expressions.

  1. ⓐ 5 2 − 4 2 +7 ( 5−4 ) 2 \sqrt{5^{2} - 4^{2}} + 7 \left(5 - 4\right)^{2}
  2. ⓑ 1+ 7⋅5−8⋅4 9−6 1 + \frac{7 \cdot 5 - 8 \cdot 4}{9 - 6}
  3. ⓒ | 1.8−4.3|+0.4 15+10 \left|1.8 - 4.3\right| + 0.4 \sqrt{15 + 10}
  4. ⓓ 1 2 [ 5⋅ 3 2 − 7 2 ]+ 1 3 ⋅ 9 2 \frac{1}{2} \left[5 \cdot 3^{2} - 7^{2}\right] + \frac{1}{3} \cdot 9^{2}
  5. ⓔ [ ( 3−8 ) 2 −4 ]−( 3−8 ) \left[\left(3 - 8\right)^{2} - 4\right] - \left(3 - 8\right)
2.5

Using Properties of Real Numbers

Use the properties of real numbers to rewrite and simplify each expression. State which properties apply.

  1. ⓐ 3⋅6+3⋅4 3 \cdot 6 + 3 \cdot 4
  2. ⓑ ( 5+8 )+( −8 ) \left(5 + 8\right) + \left(−8\right)
  3. ⓒ 6−( 15+9 ) 6 - \left(15 + 9\right)
  4. ⓓ 4 7 ⋅( 2 3 ⋅ 7 4 ) \frac{4}{7} \cdot \left(\frac{2}{3} \cdot \frac{7}{4}\right)
  5. ⓔ 100⋅[ 0.75+( −2.38 ) ] 100 \cdot \left[0.75 + \left(−2.38\right)\right]
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1.1 Exercise 17

Use the properties of real numbers to rewrite and simplify each expression. State which properties apply.

  1. ⓐ ( − 23 5 )⋅[ 11⋅( − 5 23 ) ] \left(- \frac{23}{5}\right) \cdot \left[11 \cdot \left(- \frac{5}{23}\right)\right]
  2. ⓑ 5⋅( 6.2+0.4 ) 5 \cdot \left(6.2 + 0.4\right)
  3. ⓒ 18−( 7−15 ) 18 - \left(7 −15\right)
  4. ⓓ 17 18 +[ 4 9 +( − 17 18 ) ] \frac{17}{18} + \left[\frac{4}{9} + \left(- \frac{17}{18}\right)\right]
  5. ⓔ 6⋅( −3 )+6⋅3 6 \cdot \left(−3\right) + 6 \cdot 3
2.5

Describing Algebraic Expressions

List the constants and variables for each algebraic expression.

  1. ⓐ x + 5
  2. ⓑ 4 3 π r 3 \frac{4}{3} \pi r^{3}
  3. ⓒ 2 m 3 n 2 \sqrt{2 m^{3} n^{2}}
2.5

1.1 Exercise 19

List the constants and variables for each algebraic expression.

  1. ⓐ 2πr( r+h ) 2 \pi r \left(r + h\right)
  2. ⓑ2(L + W)
  3. ⓒ 4 y 3 +y 4 y^{3} + y
2.5

Evaluating an Algebraic Expression at Different Values

Evaluate the expression 2x−7 2 x - 7 for each value for x.

  1. ⓐ x=0 x = 0
  2. ⓑ x=1 x = 1
  3. ⓒ x= 1 2 x = \frac{1}{2}
  4. ⓓ x=−4 x = −4
2.5

1.1 Exercise 21

Evaluate the expression 11−3y 11 - 3 y for each value for y.

  1. ⓐ y=2 y = 2
  2. ⓑ y=0 y = 0
  3. ⓒ y= 2 3 y = \frac{2}{3}
  4. ⓓ y=−5 y = −5
2.5

Evaluating Algebraic Expressions

Evaluate each expression for the given values.

  1. ⓐ x+5 x + 5 for x=−5 x = −5
  2. ⓑ t 2t−1 \frac{t}{2 t −1} for t=10 t = 10
  3. ⓒ 4 3 π r 3 \frac{4}{3} \pi r^{3} for r=5 r = 5
  4. ⓓ a+ab+b a + a b + b for a=11,b=−8 a = 11 , b = −8
  5. ⓔ 2 m 3 n 2 \sqrt{2 m^{3} n^{2}} for m=2,n=3 m = 2 , n = 3
2.5

1.1 Exercise 23

Evaluate each expression for the given values.

  1. ⓐ y+3 y−3 \frac{y + 3}{y - 3} for y=5 y = 5
  2. ⓑ 7−2t 7 - 2 t for t=−2 t = −2
  3. ⓒ 1 3 π r 2 \frac{1}{3} \pi r^{2} for r=11 r = 11
  4. ⓓ ( p 2 q ) 3 \left(p^{2} q\right)^{3} for p=−2,q=3 p = −2 , q = 3
  5. ⓔ 4( m−n )−5( n−m ) 4 \left(m - n\right) - 5 \left(n - m\right) for m= 2 3 ,n= 1 3 m = \frac{2}{3} , n = \frac{1}{3}
2.5

Simplifying Algebraic Expressions

Simplify each algebraic expression.

  1. ⓐ 3x−2y+x−3y−7 3 x - 2 y + x - 3 y - 7
  2. ⓑ 2r−5( 3−r )+4 2 r - 5 \left(3 - r\right) + 4
  3. ⓒ ( 4t− 5 4 s )−( 2 3 t+2s ) \left(4 t - \frac{5}{4} s\right) - \left(\frac{2}{3} t + 2 s\right)
  4. ⓓ 2mn−5m+3mn+n 2 m n - 5 m + 3 m n + n
2.5

1.1 Exercise 27

Simplify each algebraic expression.

  1. ⓐ 2 3 y−2( 4 3 y+z ) \frac{2}{3} y - 2 \left(\frac{4}{3} y + z\right)
  2. ⓑ 5 t −2− 3 t +1 \frac{5}{t} - 2 - \frac{3}{t} + 1
  3. ⓒ 4p( q−1 )+q( 1−p ) 4 p \left(q - 1\right) + q \left(1 - p\right)
  4. ⓓ 9r−( s+2r )+( 6−s ) 9 r - \left(s + 2 r\right) + \left(6 - s\right)
2.5

Simplifying a Formula

A rectangle with length L L and width W W has a perimeter P P given by P=L+W+L+W. P = L + W + L + W . Simplify this expression.

2.5

1.1 Exercise 29

If the amount P P is deposited into an account paying simple interest r r for time t, t , the total value of the deposit A A is given by A=P+Prt. A = P + P r t . Simplify the expression. (This formula will be explored in more detail later in the course.)

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1.1 Exercise 30

Is 2 \sqrt{2} an example of a rational terminating, rational repeating, or irrational number? Tell why it fits that category.

2.5

1.1 Exercise 32

What do the Associative Properties allow us to do when following the order of operations? Explain your answer.

2.5

1.1 Exercise 34

Simplify the given expression.

6÷2−( 81÷ 3 2 ) 6 \div 2 - \left(81 \div 3^{2}\right)

2.5

1.1 Exercise 36

Simplify the given expression.

−2× [ 16÷ ( 8−4 ) 2 ] 2 −2 \times \left[16 \div \left(8 - 4\right)^{2}\right]^{2}

2.5

1.1 Exercise 38

Simplify the given expression.

3( 5−8 ) 3 \left(5 - 8\right)

2.5

1.1 Exercise 40

Simplify the given expression.

12÷( 36÷9 )+6 12 \div \left(36 \div 9\right) + 6

2.5

1.1 Exercise 42

Simplify the given expression.

3−12×2+19 3 - 12 \times 2 + 19

2.5

1.1 Exercise 44

Simplify the given expression.

5+( 6+4 )−11 5 + \left(6 + 4\right) - 11

2.5

1.1 Exercise 46

Simplify the given expression.

14×3÷7−6 14 \times 3 \div 7 - 6

2.5

1.1 Exercise 48

Simplify the given expression.

6+2×2−1 6 + 2 \times 2 - 1

2.5

1.1 Exercise 50

Simplify the given expression.

9+4( 2 2 ) 9 + 4 \left(2^{2}\right)

2.5

1.1 Exercise 52

Simplify the given expression.

25÷ 5 2 −7 25 \div 5^{2} - 7

2.5

1.1 Exercise 54

Simplify the given expression.

2×4−9( −1 ) 2 \times 4 - 9 \left(−1\right)

2.5

1.1 Exercise 56

Simplify the given expression.

12( 3−1 )÷6 12 \left(3 - 1\right) \div 6

2.5

1.1 Exercise 58

Evaluate the expression using the given value of the variable.

4y+8–2y 4 y + 8 – 2 y for y=3 y = 3

2.5

1.1 Exercise 60

Evaluate the expression using the given value of the variable.

4z−2z( 1+4 )–36 4 z - 2 z \left(1 + 4\right) – 36 for z=5 z = 5

2.5

1.1 Exercise 62

Evaluate the expression using the given value of the variable.

− ( 2x ) 2 +1+3 - \left(2 x\right)^{2} + 1 + 3 for x=2 x = 2

2.5

1.1 Exercise 64

Evaluate the expression using the given value of the variable.

2( 11c−4 )–36 2 \left(11 c - 4\right) – 36 for c=0 c = 0

2.5

1.1 Exercise 66

Evaluate the expression using the given value of the variable.

1 4 ( 8w− 4 2 ) \frac{1}{4} \left(8 w - 4^{2}\right) for w=1 w = 1

2.5

1.1 Exercise 68

Simplify the expression.

2y− ( 4 ) 2 y−11 2 y - \left(4\right)^{2} y - 11

2.5

1.1 Exercise 70

Simplify the expression.

8b−4b( 3 )+1 8 b - 4 b \left(3\right) + 1

2.5

1.1 Exercise 72

Simplify the expression.

7z−3+z× 6 2 7 z - 3 + z \times 6^{2}

2.5

1.1 Exercise 74

Simplify the expression.

9( y+8 )−27 9 \left(y + 8\right) - 27

2.5

1.1 Exercise 76

Simplify the expression.

6+12b−3×6b 6 + 12 b - 3 \times 6 b

2.5

1.1 Exercise 78

Simplify the expression.

( 4 9 ) 2 ×27x \left(\frac{4}{9}\right)^{2} \times 27 x

2.5

1.1 Exercise 80

Simplify the expression.

9x+4x( 2+3 )−4( 2x+3x ) 9 x + 4 x \left(2 + 3\right) - 4 \left(2 x + 3 x\right)

2.5

1.1 Exercise 82

Consider this scenario: Fred earns $40 at the community garden. He spends $10 on a streaming subscription, puts half of what is left in a savings account, and gets another $5 for walking his neighbor’s dog.

Write the expression that represents the number of dollars Fred keeps (and does not put in his savings account). Remember the order of operations.

2.5

1.1 Exercise 84

Solve the given problem.

According to the U.S. Mint, the diameter of a quarter is 0.955 inches. The circumference of the quarter would be the diameter multiplied by π. \pi . Is the circumference of a quarter a whole number, a rational number, or an irrational number?

2.5

1.1 Exercise 86

Consider this scenario: There is a mound of g g pounds of gravel in a quarry. Throughout the day, 400 pounds of gravel is added to the mound. Two orders of 600 pounds are sold and the gravel is removed from the mound. At the end of the day, the mound has 1,200 pounds of gravel.

Write the equation that describes the situation.

2.5

1.1 Exercise 88

Solve the given problem.

Ramon runs the marketing department at their company. Their department gets a budget every year, and every year, they must spend the entire budget without going over. If they spend less than the budget, then the department gets a smaller budget the following year. At the beginning of this year, Ramon got $2.5 million for the annual marketing budget. They must spend the budg…

2.5

1.1 Exercise 90

Use a graphing calculator to solve for x. Round the answers to the nearest hundredth.

( 0.25−0.75 ) 2 x−7.2=9.9 \left(0.25 - 0.75\right)^{2} x - 7.2 = 9.9

2.5

1.1 Exercise 92

Determine whether the statement is true or false: The multiplicative inverse of a rational number is also rational.

2.5

1.1 Exercise 94

Determine whether the simplified expression is rational or irrational: −18−4( 5 )( −1 ) . \sqrt{−18 - 4 \left(5\right) \left(−1\right)} .

2.5

1.1 Exercise 96

The division of two natural numbers will always result in what type of number?

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Adapted from College Algebra © 2021 Rice University. Licensed under CC BY 4.0. Sources: College Algebra 2e, Algebra and Trigonometry 2e, Precalculus 2e, College Algebra with Corequisite Support 2e. Imported at revision 4922e46.