Math Exam 2 Answers Fall Circle the LETTER of the correct answer for #1-3.

Transcription

1 Cirle the LETTER of the orret answer for #1-3. (7 pts)1. Consider the following work of a student and selet a orret statement. There is an error with the (7 pts) is very lose to: 70 (7 pts)3. Choose the list of frations that are all less than ,,

2 (6 pts)4. This word problem uses the sharing onept of division. Mr. Malloy has 35 students and his lassroom has 7 tables. How many students sit at eah table if eah table has the same number of students? Write out the arithmeti and answer for this problem: Finish writing this new word problem about Mr. Malloy and his lass using the repeated-subtration onept of division and the SAME arithmeti. Mr. Malloy has 35 students and 7 students an sit at a table. How many tables does he need for all of his students? (8 pts)5. Miss Baker put this problem on the board: = 4682 She then wrote: =? Without hesitating, Sam wrote 2341 on his paper. What thought proess did Sam have that allowed him to answer so quikly? Sam knew that when the divisor is doubled, the quotient is ut in half. How would Sam determine the answer to this problem? =? He would take the original answer and double it beause the original dividend is doubled. Answer:

3 (12 pts)6. These piees represent an addition problem. Cirle all of the omputations shown below that ould be represented by the piees ** seven seven **Note: There was a typo on the original exam for this example. Therefore, this example was ounted orret for all students. (8 pts)7. Use the strip diagram to determine 125% of 84. Begin by labeling the strip to indiate what PERCENT it represents. Then draw whatever is neessary to solve the problem. Use labels. 100 % % 25% 25% 25% 25% Answer: 105 Note: this drawing is just ONE possibility. 3

4 (9 pts)8. Use your lose to knowledge to estimate the following answers. 21% is lose to the fration: 1/5 So 21% of 1511 is approximately: 300 or % is lose to the fration: 1/3 So 32% of 840 is approximately: is lose to the fration: 1/2 So is approximately: 550 (6 pts)9. Cirle the most reasonable answer in eah ase. 550 feet is most likely the height of the Washington monument a basketball hoop the Purdue engineering fountain 1900 miles is most likely the distane from West Lafayette to: Chiago, Illinois Cairo, Egypt San Franiso, California 360,000 pounds is most likely the weight of: an adult elephant a 747 jet plane an adult ow (8 pts)10. The earth is 150,000,000,000 meters from the sun, and the speed of light is 300,000,000 meters per seond. How many seonds does it take light to reah the earth from the sun? Begin by expressing eah number in sientifi notation. Do your work using sientifi notation. Express your answer in sientifi notation / seonds Answer: 4

5 (8 pts)11. The length of figure B is 1/2 unit. What is the length of figure C? Explain. [Hint: What is a unit?] B C 1 unit = If figure B is ½ of a unit, two of them would make one unit so six squares equal one unit. Figure C has two squares so it is 2/6 of a unit or 1/3 of a unit. (8 pts)12. a, b, and are whole numbers and a > b > > 0. Whih is larger: a or b? Explain how you know without using numbers. a When the denominators are the same, the larger fration has the larger numerator. b a or b? Explain how you know without using numbers. b When the numerators are the same, the larger fration has the smaller denominator. (6 pts)13. Determine whether the given frations have deimals that are terminating, repeating, or neither. Cirle your answer for eah