Finding the Remaining Percent of a Whole
Grade 4 students learn to find the remaining percent of a whole using the rule that all parts must total 100% in Saxon Math Intermediate 4. If 25% of a circle is shaded, then 75% is unshaded because 25% + 75% = 100%. Students apply this by subtracting a known percentage from 100 — for example, if 40% of marbles are blue, then 100% − 40% = 60% are not blue. This Chapter 5 skill introduces percentage reasoning and connects fractions to real-world contexts like probability and data analysis.
Key Concepts
Property The parts of a whole total 100%. If 25% of a circle is shaded, then 75% is not shaded because $25\% + 75\% = 100\%$.
Example If 40% of a circle is shaded, what percent is not shaded? $100\% 40\% = 60\%$ is not shaded. If 80% of the answers were correct, what percent were incorrect? $100\% 80\% = 20\%$ were not correct. If the chance of rain is 10%, what is the chance it will not rain? $100\% 10\% = 90\%$ chance of no rain.
Explanation Imagine a whole pizza is 100%. If you eat 30% of it, how much is left? Just subtract from 100! The whole of anything—a group of people, a tank of gas, or a bag of candy—always adds up to 100%. Knowing one part lets you instantly figure out the other missing part. It's a simple subtraction trick!
Common Questions
How do you find the remaining percent of a whole?
Since all parts of a whole must add up to 100%, subtract the known percentage from 100. If 40% of a circle is shaded, then 100% − 40% = 60% is not shaded.
Why do percentages always add up to 100%?
Percent means out of 100. A complete group or whole always equals 100%, so any two complementary parts — like shaded and unshaded, or correct and incorrect — must together equal 100%.
What is a common mistake with remaining percent problems?
A common mistake is using extra numbers from the problem that are not needed. For example, knowing a bag has 50 marbles is not required to find what percentage are not blue — just subtract the given percent from 100.
Can you give an example of finding the remaining percent?
If there is a 10% chance of rain, then there is a 100% − 10% = 90% chance it will not rain. If 80% of answers on a test were correct, then 100% − 80% = 20% were incorrect.
What textbook teaches remaining percent in Grade 4?
Saxon Math Intermediate 4 covers finding the remaining percent of a whole in Chapter 5 (Lessons 41–50), connecting it to fractions, data, and probability concepts.