Mathematics Grade 9 15 min

Compare fractions using benchmarks

Compare fractions using benchmarks

Tutorial Preview

1

Introduction & Learning Objectives

Learning Objectives Identify and use the key benchmarks of 0, 1/2, and 1 to compare fractions. Determine if a fraction is less than, equal to, or greater than 1/2 by comparing the numerator to half of the denominator. Determine if a fraction is less than, equal to, or greater than 1 by comparing the numerator to the denominator. Compare two fractions by analyzing their relative positions to a common benchmark. Reason about the 'distance' of a fraction from a benchmark to compare two fractions on the same side of that benchmark. Apply benchmark reasoning to evaluate the magnitude of simple rational expressions for a given value of the variable. You have 7/8 of a pizza left, and your friend has 8/10 of a pizza left. Without doing complex math, who has more? 🍕 This...
2

Key Concepts & Vocabulary

TermDefinitionExample Benchmark FractionA common, easy-to-visualize fraction (like 0, 1/2, or 1) that we use as a reference point to compare other, more complex fractions.To compare 4/9 and 5/8, we can use the benchmark of 1/2. We see that 4/9 is less than 1/2, and 5/8 is greater than 1/2. NumeratorThe top number in a fraction. It represents how many parts of the whole you have.In the fraction 3/5, the numerator is 3. DenominatorThe bottom number in a fraction. It represents the total number of equal parts the whole is divided into.In the fraction 3/5, the denominator is 5. Rational ExpressionAn expression that is the ratio of two polynomials, essentially a fraction containing variables.(x + 2) / (x - 3). Comparing fractions is a foundational skill for estimating the value of these expres...
3

Core Formulas

Comparing to the Benchmark 1 For a positive fraction \( \frac{a}{b} \): If \( a < b \), then \( \frac{a}{b} < 1 \). If \( a = b \), then \( \frac{a}{b} = 1 \). If \( a > b \), then \( \frac{a}{b} > 1 \). Use this rule to quickly determine if a fraction's value is less than, equal to, or greater than one whole by simply comparing the numerator and the denominator. Comparing to the Benchmark 1/2 For a positive fraction \( \frac{a}{b} \): If \( 2a < b \), then \( \frac{a}{b} < \frac{1}{2} \). If \( 2a = b \), then \( \frac{a}{b} = \frac{1}{2} \). If \( 2a > b \), then \( \frac{a}{b} > \frac{1}{2} \). Use this rule to determine if a fraction is less than, equal to, or greater than one-half. This is equivalent to checking if the numerator is less than...

4 more steps in this tutorial

Sign up free to access the complete tutorial with worked examples and practice.

Sign Up Free to Continue

Sample Practice Questions

Challenging
For which positive integer values of x is the rational expression (x+4)/(3x+3) greater than 1/2?
A.x < 5
B.x > 5
C.All positive integers
D.No positive integers
Challenging
You are comparing two fractions, a/b and c/d. Both are greater than 1/2 but less than 1. You find that 1 - a/b = 1/n and 1 - c/d = 1/(n+1) for some positive integer n. Which statement must be true?
A.a/b > c/d
B.a/b < c/d
C.a/b = c/d
D.More information is needed.
Challenging
Which fraction lies on a number line between 12/13 and 14/15?
A.11/12
B.15/16
C.16/17
D.13/14

Want to practice and check your answers?

Sign up to access all questions with instant feedback, explanations, and progress tracking.

Start Practicing Free

More from Rational functions and expressions

Ready to find your learning gaps?

Take a free diagnostic test and get a personalized learning plan in minutes.