Basic Mathematics for College Students

6.4 Estimation with Percent 557

SECTION 6.4 STUDY SET

VOCABULARY

Fill in the blanks.

1. can be used to find approximations when
   exact answers aren’t necessary.


2. With -end rounding, a number is rounded to its
   largest place value so that all but its first digit is zero.

CONCEPTS

Fill in the blanks.

3. To find 1% of a number, move the decimal point in
   the number places to the left.


4. To find 10% of a number, move the decimal point in
   the number place to the left.


5. To find 20% of a number, find 10% of the number by
   moving the decimal point one place to the left, and
   then double (multiply by ) the result.


6. To find 50% of a number, divide the number by.


7. To find 25% of a number, divide the number by.


8. To find 5% of a number, find 10% of the number by
   moving the decimal point in the number one place to
   the left. Then, divide that result by.


9. To find 15% of a number, find the sum of % of
   the number and % of the number.


10. To find 200% of a number, multiply the number by
    .

GUIDED PRACTICE

What is 1% of the given number? Find the exact answer and an
estimate using front-end rounding.See Example 1.

11. 275.1 12. 460.9


12. 12.67 14. 92.11

What is 10% of the given number? Find the exact answer and an
estimate using front-end rounding.See Example 2.

15. 4,059 pounds


16. 7,435 hours


17. 691.4 minutes


18. 881.2 kilometers

Estimate each answer. (Answers may vary.) See Example 3.

19. What is 20% of 346?


20. What is 20% of 409?


21. What is 20% of 67?


22. What is 20% of 32?

Estimate each answer. (Answers may vary.) See Example 4.

23. What is 50% of 4,195,898?


24. What is 50% of 6,802,117?


25. What is 50% of 397,020?


26. What is 50% of 793,288?
    Estimate each answer. (Answers may vary.) See Example 5.


27. What is 25% of 15.49?


28. What is 25% of 7.02?


29. What is 25% of 49.33?


30. What is 25% of 39.74?
    Estimate each answer. (Answers may vary because of the
    approximation used.) See Example 6.


31. What is 5% of 16,359?


32. What is 5% of 44,191?


33. What is 5% of 394.182?


34. What is 5% of 176.001?
    Estimate a 15% tip on each dollar amount. (Answers may vary.)
    See Example 7.


35. $58.99 36. $38.60


36. $27.16 38. $49.05


37. $115.75 40. $135.88


38. $9.74 42. $11.75
    Estimate each answer. (Answers may vary.) See Example 8.


39. What is 200% of 4.212?


40. What is 200% of 5.189?


41. What is 200% of 35.77?


42. What is 200% of 80.32?

TRY IT YOURSELF

Find the exact answer using methods from this section.

47. What is 2% of 600?


48. What is 3% of 700?


49. What is 30% of 18?


50. What is 40% of 45?
    Estimate each answer. (Answers may vary.)


51. What is 300% of 59.2?


52. What is 400% of 203.77?


53. What is 5% of 4,605?


54. What is 5% of 8,401?