Wednesday Sept 3

1. Important considerations for rounding:
Rounding during a calculation can lead to a less
accurate result, you need to decide how accurate
you need the answer to be in order to decide if it is
acceptable to round during a calculation.

2. To estimate quickly:
1. Round the numbers to values that you can do
mental math with
2. Do the calculation with the simplified numbers
3. Think about whether your estimate seems to big
or too small

3. Do in class: page 19 Exercises 1.5 #’s 1 - 4

4. Percentage Error – works out the difference between
the estimate and the actual value in relation to the
size of the actual value.
* the smaller the percentage error the more
accurate the estimate
Calculating percentage error:
VE = exact value VA = approximate amount

5. Do : Exercises 1.6 #’s 1 & 2 page 21

6. Standard Form (Scientific Form) - a way to express
very small or very large numbers
Form: a x 10n where a  1 ≤ a < 10
Example: 1,230 in standard form is 1.23 x 103
Example: 0.0347 in standard form is 3.47 x 10-2

7. Transforming large numbers:
1. First write down the number and place a decimal
point where the number will be between 1 and 10
2. Count the number of places the decimal has moved
3. Number of places moved is the positive power of 10
Example: 1) 3,254,000  3.254
2) then count the number of places the decimal moved, in
this case 6 places.
3) The standard form is 3.254 x 106

8. Transforming small numbers to standard form:
1. Place the decimal so the number is between 1 and 10
2. Count the number of decimal places moved
3. The number of decimal places moved is the negative
power of 10
Example:
1. 0.00056 5.6
2. Count number of decimal places moved, in this case 4
3. The standard form is 5.6 x 10-4

9. Thursday: Quiz on Real numbers, Rounding, and
Significant digits