Finding Unstated Information in Fraction Problems
Finding unstated information in fraction problems means deducing the size of the remainder group from the fraction given for one group. In Grade 6 Saxon Math Course 1 (Chapter 8: Advanced Topics in Geometry and Number Operations), students use the denominator to find the total number of equal parts, the numerator to identify one group, and subtraction (denominator minus numerator) to find the other group. For a class library where 2/7 of books are non-fiction: 7 - 2 = 5, so 5/7 are fiction. Students then use this deduced fraction to find actual counts in multi-step problems.
Key Concepts
New Concept Often fractional parts statements contain more information than what is directly stated.
What’s next Next, you will diagram these statements and answer questions to find all the hidden information.
Common Questions
How do you find unstated information in a fraction word problem?
The denominator gives the total equal parts. The numerator gives one group. Subtract numerator from denominator for the other group's fraction.
In a class library, 2/7 of books are non-fiction. What fraction are fiction?
7 - 2 = 5. Fiction = 5/7 of the books.
If 3/4 of pets in a shelter are cats, what fraction are not cats?
4 - 3 = 1. Non-cats = 1/4 of the pets.
A class has 35 students. 3/5 are girls. How many are boys?
Boys = 2/5 of students (since 5 - 3 = 2). 35/5 = 7, then 7 x 2 = 14 boys.
Why is identifying unstated information important in multi-step problems?
Many problems require knowing both portions of a group to answer a follow-up. Deducing the unstated fraction is the bridge between the given information and the final question.