Videos, worksheets, stories and songs to help Grade 9
students learn about percent of change, greatest possible error of a measurement and percent error.
Related Topics: More Math Lessons for Grade 9
Greatest possible error and rounding measurements
The greatest possible error of a measurement is how far off a measurement can be and still round to what is written. This video shows why the Greatest
Possible Error (GPE) is one half of the precision.
Calculate the percent error of a measurement
The percent error is the Greatest Possible Error (GPE) divided by the measurement multiply by 100%.
(Errata: In the first example, the given precision is
1m and so the GPE should be 0.5m).
Finding Percent of Change and Greatest Possible Error
Example 1: Find the percent of change to the nearest percent. A CD goes down in price from $15.99 to $9.99
Find the percent of change to the nearest percent. A CD goes up in price from $9.99 to $15.99
Example 3: The weight scales shows a weight of 145.2 pounds. What is the
greatest possible error?
Example 4: A measurement is 6 feet?
What is the
greatest possible error?
Calculating percent of change and greatest possible error.
Percent of change
is the amount of change divided by the original amount.
Example 1: The price of a shirt decreased from $32.95 to $28.95. Find the percent of decrease.
Example 2: Between 1940 and 1980, the federal budget increased from $9.5 billion to $725.3 billion. What was the persent of increase in the budget?
The Greatest Possible Error is one half of the measuring unit.
Example 3: You read the bathroom scale as 122 lb. What is your greatest possible error? What is your % error?
Example 4: When the garden plot was measured, the dimensions were 156 in by 84
in. Use the greatest possible error to find the minimum and maximum possible areas. What is your % error?
Example 5: Supose you measure a library book and record its width as
17.6 cm. Find the percent of error in your measurement.
Example 6: A small jewelry box measures 7.4cm by 12.2cm by 4.2cm. Find the percent error in calculating the volume.
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