GED Number Operations Practice Questions, Set 2

This is set 2 of 3 for GED Number Operations, with 21 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 21

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A machine part must be 2.45 cm thick, give or take 0.03 cm. Which thickness is NOT acceptable?

Number Operations practice set 2: 21 questions with answers

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

  1. 1.A machine part must be 2.45 cm thick, give or take 0.03 cm. Which thickness is NOT acceptable?

    1. A.2.42 cm
    2. B.2.49 cm
    3. C.2.44 cm
    4. D.2.47 cm
    Show answer

    Answer: B. 2.49 cm

    Acceptable parts satisfy |t − 2.45| ≤ 0.03, which is 2.42 to 2.48 cm. A 2.49 cm part is 0.04 cm off; 2.42 cm sits right at the limit and is still allowed.

  1. 2.A nurse must give a patient 1.5 liters of fluid. How many milliliters is that?

    1. A.150 mL
    2. B.1,500 mL
    3. C.15,000 mL
    4. D.0.0015 mL
    Show answer

    Answer: B. 1,500 mL

    There are 1,000 milliliters in a liter, so 1.5 × 1,000 = 1,500 mL. Choice 150 mL multiplies by 100 instead of 1,000.

  1. 3.A factory machine fills 18 bottles per minute. How many bottles does it fill in a 7.5-hour shift?

    1. A.135
    2. B.1,080
    3. C.8,100
    4. D.810
    Show answer

    Answer: C. 8,100

    7.5 hours is 7.5 × 60 = 450 minutes, and 18 × 450 = 8,100 bottles. Choice 135 multiplies 18 by 7.5 without converting hours to minutes.

  1. 4.Round 6,482.759 to the nearest hundredth.

    1. A.6,482.76
    2. B.6,482.75
    3. C.6,482.8
    4. D.6,500
    Show answer

    Answer: A. 6,482.76

    The hundredths digit is 5 and the digit after it is 9, so round up to 6,482.76. Choice 6,500 rounds to the nearest hundred instead of the nearest hundredth.

  1. 5.A town of 18,940 residents raised $95,310 for a new playground. About how much is that per resident?

    1. A.$50.00
    2. B.$5.00
    3. C.$0.50
    4. D.$500.00
    Show answer

    Answer: B. $5.00

    Round to $95,000 and 19,000 residents. Then 95,000 ÷ 19,000 = 5, so about $5.00 each. Choice $50.00 drops a zero from the population when rounding.

  1. 6.A worker earns $16.40 per hour and works 37.5 hours in a week. What is the gross pay?

    1. A.$61.50
    2. B.$598.50
    3. C.$615.00
    4. D.$656.00
    Show answer

    Answer: C. $615.00

    Multiply: 16.40 × 37.5 = 615, so the pay is $615.00. Choice $61.50 places the decimal point one place too far left.

  1. 7.A board is 2.4 meters long. A carpenter cuts off pieces that are 0.85 m and 1.075 m long. How much of the board is left?

    1. A.1.325 m
    2. B.0.525 m
    3. C.0.475 m
    4. D.1.55 m
    Show answer

    Answer: C. 0.475 m

    The cuts total 0.85 + 1.075 = 1.925 m, and 2.400 − 1.925 = 0.475 m. Choice 1.55 m subtracts only the first piece.

  1. 8.Hot dogs come in packs of 10 and buns come in packs of 8. What is the smallest number of hot dogs you can buy to have exactly as many buns as hot dogs?

    1. A.80
    2. B.40
    3. C.18
    4. D.20
    Show answer

    Answer: B. 40

    You need the least common multiple of 10 and 8. The multiples of 10 are 10, 20, 30, 40, and 40 is the first that is also a multiple of 8. Choice 80 is a common multiple, 10 × 8, but not the least one.

  1. 9.Light travels about 3 × 10⁵ kilometers per second. About how many kilometers does it travel in 2 × 10³ seconds?

    1. A.6 × 10⁸
    2. B.1.5 × 10²
    3. C.6 × 10¹⁵
    4. D.5 × 10⁸
    Show answer

    Answer: A. 6 × 10⁸

    Multiply the numbers, 3 × 2 = 6, and add the exponents, 5 + 3 = 8, to get 6 × 10⁸ km. Choice 6 × 10¹⁵ multiplies the exponents instead of adding them.

  1. 10.Evaluate without a calculator: 7 − 3[2 + (5 − 8)²]

    1. A.−26
    2. B.44
    3. C.28
    4. D.−20
    Show answer

    Answer: A. −26

    Work from the inside out: 5 − 8 = −3, (−3)² = 9, and 2 + 9 = 11. Then 3 × 11 = 33 and 7 − 33 = −26. Choice 44 subtracts 7 − 3 first, but multiplication comes before subtraction.

  1. 11.What is 2.7 ÷ 0.045?

    1. A.0.06
    2. B.6
    3. C.600
    4. D.60
    Show answer

    Answer: D. 60

    Move both decimal points three places to the right: 2,700 ÷ 45 = 60. Choice 6 moves the decimal in 2.7 only two places, which gives 270 ÷ 45.

  1. 12.Which expression has the greatest value?

    1. A.|−9| − |3|
    2. B.−|−9 + 3|
    3. C.|−9 − 3|
    4. D.−9 − |3|
    Show answer

    Answer: C. |−9 − 3|

    Inside the bars, −9 − 3 = −12, and its absolute value is 12, the largest. Choice |−9| − |3| equals 9 − 3 = 6.

  1. 13.A city’s yearly budget is $4.2 × 10⁸ and its population is 6 × 10⁵. What is the budget per resident?

    1. A.$7,000
    2. B.$700
    3. C.$70,000
    4. D.$70
    Show answer

    Answer: B. $700

    Divide the numbers and subtract the exponents: 4.2 ÷ 6 = 0.7 and 10⁸ ÷ 10⁵ = 10³, so 0.7 × 10³ = $700. Choice $7,000 treats 4.2 ÷ 6 as 7.

  1. 14.Which is the prime factorization of 180?

    1. A.2 × 3² × 5
    2. B.2² × 3 × 5
    3. C.2² × 3² × 5²
    4. D.2² × 3² × 5
    Show answer

    Answer: D. 2² × 3² × 5

    180 = 2 × 90 = 2 × 2 × 45 = 2 × 2 × 3 × 3 × 5, which is 2² × 3² × 5. Choice 2 × 3² × 5 equals 90 because it is missing one factor of 2.

  1. 15.Which list orders these numbers from greatest to least? 0.45, 4/9, 0.4, 3/7

    1. A.3/7, 4/9, 0.45, 0.4
    2. B.4/9, 0.45, 3/7, 0.4
    3. C.0.45, 4/9, 0.4, 3/7
    4. D.0.45, 4/9, 3/7, 0.4
    Show answer

    Answer: D. 0.45, 4/9, 3/7, 0.4

    As decimals, 4/9 ≈ 0.444 and 3/7 ≈ 0.429, so the order is 0.45, 0.444, 0.429, 0.4. Choice 4/9, 0.45, 3/7, 0.4 assumes 4/9 is larger than 0.45, but 0.444 is smaller.

  1. 16.A worker drives 38.6 miles each way to work, 5 days a week. Which is the best estimate of the miles driven to and from work in 4 weeks?

    1. A.About 3,200 miles
    2. B.About 1,600 miles
    3. C.About 200 miles
    4. D.About 800 miles
    Show answer

    Answer: B. About 1,600 miles

    Round 38.6 to 40. Each day is 2 × 40 = 80 miles, a week is 5 × 80 = 400 miles, and 4 weeks is about 1,600 miles. Choice About 800 miles counts only one direction each day.

  1. 17.A conveyor belt moves at 90 feet per minute. What is that speed in inches per second?

    1. A.1.5
    2. B.1,080
    3. C.45
    4. D.18
    Show answer

    Answer: D. 18

    Multiply by 12 to get inches: 90 × 12 = 1,080 inches per minute. Divide by 60 for seconds: 1,080 ÷ 60 = 18. Choice 1,080 changes feet to inches but never changes minutes to seconds.

  1. 18.What is 0.36 ÷ 1.2?

    1. A.0.3
    2. B.3
    3. C.0.03
    4. D.0.432
    Show answer

    Answer: A. 0.3

    Move both decimal points one place: 3.6 ÷ 12 = 0.3. Choice 0.432 multiplies the numbers instead of dividing.

  1. 19.Evaluate: (−2)³ − 3(4 − 10) ÷ 2

    1. A.19
    2. B.−17
    3. C.−1
    4. D.1
    Show answer

    Answer: D. 1

    (−2)³ = −8 and 3(−6) ÷ 2 = −9, so −8 − (−9) = −8 + 9 = 1. Choice −17 subtracts 9 instead of subtracting −9.

  1. 20.What is the value of (2/3)² × 3³?

    1. A.12
    2. B.36
    3. C.18
    4. D.4
    Show answer

    Answer: A. 12

    (2/3)² = 4/9 and 3³ = 27, so 4/9 × 27 = 12. Choice 18 forgets to square 2/3 and computes 2/3 × 27.

  1. 21.A cell is about 1.2 × 10⁻⁵ meter wide. A grain of sand is about 6 × 10⁻⁴ meter wide. About how many times wider is the grain of sand?

    1. A.500
    2. B.0.02
    3. C.50
    4. D.5
    Show answer

    Answer: C. 50

    Divide: 6 ÷ 1.2 = 5 and 10⁻⁴ ÷ 10⁻⁵ = 10¹, so the ratio is 5 × 10 = 50. Choice 0.02 divides the cell by the sand grain, which gives how much of the grain one cell covers.

More practice sets

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