1. 1
Introduction to Algebra:
Integers

2. R.1 Fractions
1.5 Problem Solving: Rounding and Estimating
Objectives
Locate the place to which a number is to be rounded.
Round integers.
Use front end rounding to estimate answers in addition and subtraction.

3. Locate the place to which a number is to be rounded.
Rounding a number means finding a number that is close to the original number, but easier to work with.

4. Locate the place to which a number is to be rounded.
Draw a line under the place to which the number is to be rounded.
Example
Round 23 to the nearest ten. Is –23 closer to –20 or –30?
–23 is closer to –20

5. Locate the place to which a number is to be rounded.
Draw a line under the place to which the number is to be rounded.
Example
Round –54,702 to the nearest thousand. Is it closer to –54,000 or –55,000?
–54,702 is closer to –55,000

6. Round integers.

7. Round integers.
Example
Round 349 to the nearest hundred.
Step 1
Underline the place to which the number is being rounded.

8. Round integers.
Example
Round 349 to the nearest hundred.
Step 2
Because the next digit is 4 or less, do not change the digit in the underlined place.

9. Round integers.
Example
Round 349 to the nearest hundred.
Step 3
Change all digits to the right of the underlined place to zeros.

10. Round integers.
Round 36,833 to the nearest thousand.
Example
Step 1
Underline the place to which the number is being rounded.

11. Round integers.
Round 36,833 to the nearest thousand.
Example
Step 2
Because the next digit is 5 or more, add 1 to the underlined digit.

12. Round integers.
Round 36,833 to the nearest thousand.
Example
Step 3
Change all digits to the right of the underlined place to zeros.

13. Round integers.
Round 13,961 to the nearest hundred.
Example
Step 1

14. Round integers.
Round 13,961 to the nearest hundred.
Example
Step 2

15. Round integers.
Round 13,961 to the nearest hundred.
Example
Step 3

16. Use front end rounding to estimate answers in addition and subtraction.
If you purchase a sofa for $988 and a chair for $209, you may estimate the total cost.

17. Use front end rounding to estimate answers in addition and subtraction.
In front end rounding, each number is rounded to the highest possible place, so all the digits become 0 except the first digit.

18. Estimate: Front end rounding:
Use front end rounding to estimate answers in addition and subtraction.
Meisha’s paycheck showed gross pay of $823. It also listed deductions of $291. What is her net pay after deductions?
Example
Estimate: Front end rounding:
Net pay estimate: $800 – $300 = $500.

19. Use front end rounding to estimate answers in addition and subtraction.
Meisha’s paycheck showed gross pay of $823. It also listed deductions of $291. Find her exact net pay.
Example
Exact pay:
$823 – $291 = $532