GED Number Operations Practice Questions, Set 3

This is set 3 of 3 for GED Number Operations, with 20 practice questions that are not part of any full practice test. If a question type feels unfamiliar, review the Number Operations study guide first, then check each answer below.

Question 1 of 20

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A banquet hall has 156 chairs to set at tables, with the same number of chairs at every table. Which table size leaves no chairs left over?

Number Operations practice set 3: 20 questions with answers

Work each question on paper first, then open the answer to check your reasoning.

  1. 1.A banquet hall has 156 chairs to set at tables, with the same number of chairs at every table. Which table size leaves no chairs left over?

    1. A.14 chairs per table
    2. B.12 chairs per table
    3. C.9 chairs per table
    4. D.8 chairs per table
    Show answer

    Answer: B. 12 chairs per table

    156 ÷ 12 = 13 exactly, so 12 is a factor of 156. Choice 8 chairs per table looks likely because 156 is even, but 156 ÷ 8 = 19.5.

  1. 2.A room has 180 square feet of floor space. Carpet is sold by the square yard. How many square yards of carpet cover the floor? (1 yard = 3 feet)

    1. A.540 square yards
    2. B.45 square yards
    3. C.60 square yards
    4. D.20 square yards
    Show answer

    Answer: D. 20 square yards

    One square yard is 3 ft × 3 ft = 9 square feet, so 180 ÷ 9 = 20 square yards. Choice 60 square yards divides by 3, which converts lengths, not areas.

  1. 3.A store manager orders 48 cases of paper towels at $31.85 per case. Which is the best estimate of the total cost?

    1. A.$1,500
    2. B.$1,200
    3. C.$15,000
    4. D.$1,900
    Show answer

    Answer: A. $1,500

    Round to 50 cases at about $30 each, or 48 × $32, both near $1,500. Choice $15,000 is off by a factor of 10, which usually means a misplaced decimal point.

  1. 4.A freezer is set to −18°C. During a power outage, its temperature rises 3.5°C each hour. What is the temperature after 4 hours?

    1. A.−4°C
    2. B.4°C
    3. C.−14.5°C
    4. D.−32°C
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    Answer: A. −4°C

    The temperature rises 4 × 3.5 = 14 degrees, so −18 + 14 = −4°C. Choice −32°C subtracts the rise instead of adding it.

  1. 5.Which number is NOT between −2 and −1 on a number line?

    1. A.−2.1
    2. B.−1.05
    3. C.−3/2
    4. D.−7/4
    Show answer

    Answer: A. −2.1

    −2.1 is farther left than −2, so it lies outside the interval. The others, −1.75, −1.05, and −1.5, are all between −2 and −1.

  1. 6.Without a calculator, which is the best estimate of 397 ÷ 7.9?

    1. A.500
    2. B.40
    3. C.5
    4. D.50
    Show answer

    Answer: D. 50

    Round 397 to 400 and 7.9 to 8, then 400 ÷ 8 = 50. Choice 5 misplaces the decimal point by one place.

  1. 7.A garden hose is 50 feet long. How many hoses, connected end to end, are needed to reach a spot 120 yards away? (1 yard = 3 feet)

    1. A.3 hoses
    2. B.8 hoses
    3. C.7 hoses
    4. D.10 hoses
    Show answer

    Answer: B. 8 hoses

    120 yards is 120 × 3 = 360 feet, and 360 ÷ 50 = 7.2, so 8 hoses are needed to reach the full distance. Choice 7 hoses leaves 10 feet short.

  1. 8.A fuel tank is 5/8 full. After 12 gallons are used, it is 1/4 full. How many gallons does the full tank hold?

    1. A.48 gallons
    2. B.4.5 gallons
    3. C.32 gallons
    4. D.19.2 gallons
    Show answer

    Answer: C. 32 gallons

    The 12 gallons used equal 5/8 − 2/8 = 3/8 of the tank, so the tank holds 12 ÷ 3/8 = 32 gallons. Choice 48 gallons treats the 12 gallons as 1/4 of the tank.

  1. 9.Gas costs $3.48 per gallon. How much do 12.5 gallons cost?

    1. A.$4.35
    2. B.$435.00
    3. C.$41.76
    4. D.$43.50
    Show answer

    Answer: D. $43.50

    3.48 × 12.5 = 43.5, so the cost is $43.50. Choice $41.76 multiplies by 12 and leaves out the extra half gallon.

  1. 10.What is the value of −3 × (−4) − |−8 + 2|?

    1. A.22
    2. B.18
    3. C.6
    4. D.−18
    Show answer

    Answer: C. 6

    −3 × (−4) = 12, and |−8 + 2| = |−6| = 6, so 12 − 6 = 6. Choice 18 adds the absolute value instead of subtracting it.

  1. 11.A gardener plants 54 tomato plants and 72 pepper plants. Each row holds only one kind of plant, and every row has the same number of plants. What is the greatest number of plants each row can have?

    1. A.9
    2. B.6
    3. C.216
    4. D.18
    Show answer

    Answer: D. 18

    The greatest common factor of 54 and 72 is 18, since 54 = 18 × 3 and 72 = 18 × 4. Choice 216 is the least common multiple, which is larger than both counts.

  1. 12.What is the value of ∛64 + 4⁻¹ × 8?

    1. A.6
    2. B.34
    3. C.−28
    4. D.36
    Show answer

    Answer: A. 6

    ∛64 = 4 and 4⁻¹ = 1/4, so 1/4 × 8 = 2 and 4 + 2 = 6. Choice −28 treats 4⁻¹ as −4.

  1. 13.A machine needs oil every 15 days and a new filter every 25 days. Both were done today. In how many days will both be due on the same day again?

    1. A.75
    2. B.40
    3. C.375
    4. D.5
    Show answer

    Answer: A. 75

    Find the least common multiple of 15 and 25: 15, 30, 45, 60, 75, and 75 is also a multiple of 25. Choice 375 multiplies the two numbers, which is a common multiple but not the least.

  1. 14.Which of these numbers is prime?

    1. A.57
    2. B.59
    3. C.91
    4. D.51
    Show answer

    Answer: B. 59

    59 has no factors other than 1 and itself. The others are not prime: 51 = 3 × 17, 57 = 3 × 19, and 91 = 7 × 13.

  1. 15.On a number line, √47 falls between which two whole numbers?

    1. A.5 and 6
    2. B.7 and 8
    3. C.6 and 7
    4. D.23 and 24
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    Answer: C. 6 and 7

    6² = 36 and 7² = 49, and 47 is between them, so √47 is between 6 and 7. Choice 23 and 24 halves 47 instead of taking its square root.

  1. 16.Which value is greatest?

    1. A.38.6%
    2. B.7/18
    3. C.3/8
    4. D.0.385
    Show answer

    Answer: B. 7/18

    As decimals: 7/18 ≈ 0.389, 0.385, 3/8 = 0.375, and 38.6% = 0.386. So 7/18 is greatest. Choice 38.6% is close but smaller.

  1. 17.A board 7 1/2 feet long is cut into pieces that are each 5/8 foot long. How many pieces can be cut?

    1. A.8
    2. B.15
    3. C.12
    4. D.4 11/16
    Show answer

    Answer: C. 12

    Divide: 15/2 ÷ 5/8 = 15/2 × 8/5 = 120/10 = 12. Choice 4 11/16 multiplies the two lengths instead of dividing.

  1. 18.A shopper buys items priced $19.85, $6.12, $31.07, and $12.90. Rounding each price to the nearest dollar, what is the best estimate of the total?

    1. A.$60
    2. B.$70
    3. C.$80
    4. D.$65
    Show answer

    Answer: B. $70

    Rounded, the prices are 20 + 6 + 31 + 13 = 70. The exact total is $69.94, so $70 is very close. Choice $60 rounds everything down.

  1. 19.Round 0.04682 to the nearest thousandth.

    1. A.0.047
    2. B.0.046
    3. C.0.05
    4. D.0.0468
    Show answer

    Answer: A. 0.047

    The thousandths digit is 6, and the next digit is 8, so round up to 0.047. Choice 0.046 drops the extra digits without rounding up.

  1. 20.Peppers cost $3.20 per pound and grapes cost $4.60 per pound. What is the cost of 2.75 pounds of peppers and 1.5 pounds of grapes?

    1. A.$7.80
    2. B.$14.70
    3. C.$16.20
    4. D.$15.70
    Show answer

    Answer: D. $15.70

    Peppers: 2.75 × 3.20 = 8.80. Grapes: 1.5 × 4.60 = 6.90. Total: 8.80 + 6.90 = $15.70. Choice $7.80 adds the two prices per pound.

More practice sets

Number Operations has 3 practice sets. None of these questions appear in the full practice tests.