Review the key concepts, formulae, and examples before starting your quiz.
๐Concepts
A rational number is defined as a number that can be expressed in the form , where and are integers and . Visually, if you look at a number line, rational numbers fill the gaps between integers, representing parts of a whole.
Equivalent rational numbers are different representations of the same value. For example, on a number line, the fractions , , and all point to the exact same spot halfway between and .
To find an equivalent rational number, you can multiply both the numerator and the denominator by the same non-zero integer. Visually, this is like taking a shaded region of a rectangle and dividing every part into smaller, equal pieces; the total shaded area remains the same.
You can also find equivalent rational numbers by dividing both the numerator and the denominator by their common divisor. This process is often called 'simplifying' or 'reducing' the fraction to its lower terms.
A rational number is in its standard form if the denominator is a positive integer and the numerator and denominator have no common factor other than . In a diagram, this represents the most basic way to express that specific ratio.
Two rational numbers and are equal if and only if . This is known as the cross-multiplication test for equivalence. If you visualize two proportional rectangles, the product of the extremes equals the product of the means.
Every rational number has an infinite number of equivalent rational numbers. You can keep scaling the numerator and denominator by any integer to generate a new version of the same value.
๐Formulae
General form of a rational number:
Equivalent by multiplication: (where )
Equivalent by division: (where is a common divisor and )
Condition for equality:
๐กExamples
Problem 1:
Find three equivalent rational numbers for .
Solution:
Step 1: Multiply both numerator and denominator by : \n \nStep 2: Multiply both numerator and denominator by : \n \nStep 3: Multiply both numerator and denominator by : \n \nTherefore, three equivalent rational numbers are , , and .
Explanation:
To find equivalent rational numbers, we multiply the numerator and the denominator by the same non-zero integers (, , and ). This changes the appearance of the fraction without changing its actual value.
Problem 2:
Check if and are equivalent rational numbers.
Solution:
Step 1: Identify the values for cross-multiplication: . \nStep 2: Calculate the product of the numerator of the first and the denominator of the second (): \n \nStep 3: Calculate the product of the denominator of the first and the numerator of the second (): \n \nStep 4: Compare the results. Since , the products are equal.
Explanation:
We used the cross-multiplication method () to verify equivalence. Since both products are , the two rational numbers represent the same value and are therefore equivalent.