Title: Unit 3 Quiz
Course: Technical Math for Industry

Q: Write 7.630 in word form.
- seven and sixty-three thousandths (Incorrect. The number to the right of the decimal point is six hundred thirty, not sixty-three.)
- seven and sixty-three ten-thousandths (Incorrect. The number to the right of the decimal point is six hundred thirty, not sixty-three. Also, there are three places to the right of the decimal point, so the last word in the word form should be "thousandths.")
- seven and six hundred thirty ten-thousandths (Incorrect. There are three places to the right of the decimal point, so the last word in the word form should be "thousandths.")
- seven and six hundred thirty thousandths (Correct. First write the word form of the number to the left of the decimal point, then the word "and," then the word form of the number to the right of the decimal point, followed by the place value of the last digit (thousandths).)
A: seven and six hundred thirty thousandths

Q: Write 0.32 as a simplified fraction.
A: (a choice with no text)
If wrong: Incorrect. You may have divided 32 by 1,000 instead of by 100.
If wrong: Incorrect. You may have simplified . You need to simplify .
If right: Correct. The number 0.32 can be written as , which simplifies to .
If wrong: Incorrect. You may have forgotten to divide the numerator by 2 during one step in simplification. Remember to divide both the numerator and denominator each time you simplify.

Q: Convert to a decimal.
- 0.15 (Correct. When the numerator, 3, is divided by the denominator, 20, the result is the decimal 0.15.)
- 0.015 (Incorrect. The decimal point is in the wrong place. When you use long division, make sure that your decimal points line up.)
A: 0.15
If wrong: Incorrect. This is the result of dividing 3 by 100. If you are solving to find the decimal, make sure to multiply the numerator and denominator by the same number.
If wrong: Incorrect. This is the result of dividing 20 by 3. You need to divide 3 by 20 to get the decimal.

Q: Which of the following sentences is true? Use the number line to help you decide.
- 6.8 is greater than 6.5. (Correct. 6.8 is to the right of 6.5 on the number line, so 6.8 is greater than 6.5.)
- 6.3 is less than 6.2. (Incorrect. Check to see if 6.3 is to the right or left of of 6.2 on the number line.)
- 6.6 is less than 6.0. (Incorrect. Check to see if 6.6 is to the right or left of 6.0 on the number line.)
- 6.4 is greater than 6.9. (Incorrect. Check to see if 6.4 is to the right or left of 6.9 on the number line.)
A: 6.8 is greater than 6.5.

Q: Which of the following sentences is true?
- 6.483 is less than 6.453. (Incorrect. In the hundredths place, 8 is greater than 5, while the digits in the other places are the same. This makes the first number greater than the second number.)
- 17.871 is greater than 17.851. (Correct. In the hundredths place, 7 is greater than 5, while the digits in the other places are the same. This makes the first number greater than the second number.)
- 19.322 is greater than 19.422. (Incorrect. In the tenths place, 3 is less than 4, while the digits in the other places are the same. This makes the first number less than the second number.)
- 26.359 is less than 26.357. (Incorrect. In the thousandths place, 9 is greater than 7, while the digits in the other places are the same. This makes the first number greater than the second number.)
A: 17.871 is greater than 17.851.

Q: Which of the following sentences is true?
A: (a choice with no text)
If wrong: Incorrect. The digits are the same until the hundredths place, where , so .
If wrong: Incorrect. Remember that . Now compare the digits of 17.40 and 17.54. The digits in the tens and ones places are the same. Comparing the tenths place, , so .
If wrong: Incorrect. The digits in the tens and ones place are the same. Comparing the digits in the tenths place, , so .
If right: Correct. , and because the digits in the ones, tenths, and hundredths places are the same, and in the thousandths place 0 is less than 3.

Q: Round 7,165.482 to the nearest hundredth.
- 7,200 (Incorrect. You rounded to the nearest hundred. You should have rounded to the nearest hundredth.)
- 7,165.5 (Incorrect. You rounded to the nearest tenth. You should have rounded to the nearest hundredth.)
- 7,165.49 (Incorrect. You rounded up when you should have rounded down.)
- 7,165.48 (Correct. You were right to round down, because the 2 in 7,165.482 is less than 5.)
A: 7,165.48

Q: Add.
- 17.938 (Incorrect. This would have been correct for the problem . You can only remove zeros from the end of a decimal.)
- 17.641 (Correct. Rewrite 11 as 11.000. Then line up the decimal points and add.)
- 6.652 (Incorrect. Rewrite 11 as 11.000 and line up the decimal points before adding. Don't line up the right-most digits before adding.)
- 18.01 (Incorrect. This would have been correct for the problem . You can only remove zeros from the end of a decimal.)
A: 17.641

Q: Subtract.
- 17.022 (Incorrect. This would have been correct for the problem . You can only add zeros to the end of a decimal.)
- 17.22 (Incorrect. This would have been correct for the problem . You can only remove zeros from the end of a decimal.)
- 17.472 (Incorrect. This would have been correct for the problem . You can only add zeros to the end of a decimal.)
- 17.526 (Correct. Line up the two numbers so that the decimal points are aligned, and then subtract.)
A: 17.526

Q: Zach has a credit card with a $500 limit. He has used the card to pay $120.32 for groceries. How much more can Zach spend without going over his limit?
- $620.32 (Incorrect. Subtract the amount spent from the limit. Don't add the amount to the limit.)
- $380.32 (Incorrect. This would be the result of the subtraction .)
- $380.68 (Incorrect. Don't forget to take away a 1 in the ones place when regrouping.)
- $379.68 (Correct.)
A: $379.68

Q: Multiply.
- 0.89628 (Incorrect. Pay attention to the placement of the decimal point. The factors have a total of four decimal places, so the product should also have four decimal places.)
- 0.089628 (Incorrect. Pay attention to the placement of the decimal point. The factors have a total of four decimal places, so the product should also have four decimal places.)
- 8.9628 (Correct. To find the product, multiply . Count the total number of decimal places in the factors, four, and then place a decimal point in the product so that the product has four decimal places as well.)
- 89.628 (Incorrect. Pay attention to the placement of the decimal point. The factors have a total of four decimal places, so the product should also have four decimal places.)
A: 8.9628

Q: Multiply.
- 0.0003128 (Incorrect. You moved the decimal point three places to the left, but it should be moved three places to the right.)
- 312.8 (Correct. To multiply by 1,000, move the decimal point three places to the right.)
- 3,128 (Incorrect. You moved the decimal point four places to the right, but it should be moved three places to the right, because 1,000 has three zeros. Count the number of zeros, not the number of digits.)
- 0.003128 (Incorrect. You moved the decimal point two places to the left, but it should be moved three places to the right.)
A: 312.8

Q: Divide.
- 8.01 (Incorrect. You may have moved the decimal point in 0.45 and forgotten to move the decimal point in 360.45. Move the decimal point in both numbers two places to the right. (This will replace 0.45 with a whole number.) Then divide.)
- 360 (Incorrect. This is a division problem, not a subtraction problem.)
- 80.1 (Incorrect. Multiply both the divisor and the dividend by 100. (This will replace 0.45 with a whole number.) Then divide.)
- 801 (Correct. This problem can be set up as .)
A: 801

Q: Divide.
- 53,178 (Incorrect. The decimal point has been moved two places to the right. This would be the answer if you multiplied by 100.)
- 0.0053178 (Incorrect. 100 has two zeros, so the decimal point gets moved two places to the left. This is not the same as having two zeros after the decimal point.)
- 0.53178 (Incorrect. The decimal point has been moved three places to the left. You should count the number of zeros, not the number of digits, in 100. The decimal point should be moved two places to the left.)
- 5.3178 (Correct. 100 has two zeros, so the decimal point gets moved two places to the left.)
A: 5.3178

Q: A club has a total of $1,520.50 in its bank account. At a budget meeting they decide to set aside 0.28 times the total amount for travel. How much money will they set aside for travel?
- $42.574 (Incorrect. Multiply the two numbers. You should have four decimal places at first, but you may drop zeros from the end of a decimal.)
- $425.74 (Correct.)
- $4.2574 (Incorrect. Multiply the two numbers. You should have four decimal places at first, but you may drop zeros from the end of a decimal.)
- $4,257.40 (Incorrect. This is greater than the total budget. After you multiply, you should have four decimal places at first, but you may drop zeros from the end of a decimal.)
A: $425.74

Q: Sean has $75 to spend on CDs. If each CD costs $6.98, about how many CDs can he buy?
- 10 (Correct. 6.98 rounds up to 7, and then . This means he has enough for 10 CDs, and not enough for 11 CDs.)
- 7 (Incorrect. You may have rounded 6.98 to 7, which is correct, but then mistakenly chosen that as your answer. You must divide the total amount, $75, by the estimated cost of one, $7.)
- 12 (Incorrect. You may have rounded 6.98 to 6, divided , and then rounded 12R3 down to 12. A better estimate is provided by rounding 6.98 to 7, then performing the division.)
- 13 (Incorrect. You may have rounded 6.98 to 6, divided , and then rounded 12R3 up to 13. A better estimate is provided by rounding 6.98 to 7, then performing the division.)
A: 10