Vocabulary

Rational Number – A Rational number is a number that can be written as a comparison of two integers (ratio), expressed as a fraction.

Concept

Identify rational numbers.

Rules

A rational number is any number that can be written as a fraction. If a given number can be rewritten as a fraction, then it is a Rational Number. 

Change a percent to a fraction: A percent implies a number out of 100. x% can be written as x100

Change a mixed number to a fraction: Convert the mixed number to an improper fraction. 

Change a decimal number to a fraction: A decimal number can be changed to a fraction by writing the digits to the right of the decimal over the number’s place value. 

Change a square root to a fraction: This can only be done if the square root can be reduced to an integer. 

Change an integer to a fraction: All integers can be written with a 1 in the denominator which makes it a fraction.

Example

Select all of the rational numbers below.

Solution

Rational numbers can all be written as fractions. 

7.2% = 721000

0.05 = 51000

47 is already a fraction.

The only number out of those choices that is irrational is √10 because 10 is not a perfect square.

Pre-requisite Skills

Compare and Order Rational Numbers (7.4.2)