Adding & Subtracting Fractions

Adding & Subtracting Fractions
••• http://www.freemathhelp.com/images/lessons/commondem.png

Adding and subtracting fractions is easy when the denominators are the same. (The denominator is the bottom number in the fraction; the top number is called the numerator.) When fractions have different denominators, there are a few steps you have to follow to find a common denominator so the fractions can be added to or subtracted from each other.

    Pick the larger denominator of the two fractions you are adding or subtracting. In the problem 1/3 + 1/2, 3 is the larger denominator of the two fractions.

    List the multiples of the larger denominator. A multiple is a number that another number divides into evenly. In our example, multiples of 3 are 3, 6, 9, 12, 15 and so on.

    Find multiples for the smaller denominator. The multiples of 2 are 2, 4, 6, 8, 10 and so on.

    Choose the smallest multiple that is common to both denominators. Six is a common multiple of both 3 and 2. This is the least common denominator.

    Find the least common denominator for both fractions. (See Section 1.) In the example 1/3 + 1/2, 6 is the least common denominator of both fractions.

    Rename both fractions using the least common denominator. In the example 1/3 + 1/2, you would write both denominators as a 6.

    Change the numerators to make equal fractions. Multiply the top number by the number you multiplied by the denominator to get the least common denominator. In the example, 1/3 + 1/2 becomes 2/6 + 3/6. The fraction 1/3 is multiplied by 2 because 3 x 2 = 6. The fraction 1/2 is multiplied by 3 because 2 x 3 = 6.

    Finish the problem by either adding or subtracting. In the example of 2/6 + 3/6, the answer is 5/6.

Related Articles

How to Write Two Fractions That Are Equivalent to a...
How to Use a Calculator to Find Ratios
How to Convert RPM to MPH With a Calculator
How to Evaluate Fractions
How to Calculate Wheel Circumference
How to Subtract, Add & Simplify Fractions
How to Convert a Fraction to a Ratio
How to Compare LCD & LCM in Fifth Grade Math
What Are Equivalent & Nonequivalent Fractions?
How to: Improper Fractions Into Proper Fractions
How to Change Decimals Into Mixed Numbers
How to Change Improper Fractions to a Mixed Number
How to Convert a Decimal to a Whole Number
How to Write Two Fractions That Are Equivalent to a...
How to Teach Kids to Add & Subtract
How to Find the Least Common Denominator of Two Fractions
How to Convert Inches to 16ths of an Inch
Definition of Mean, Median & Mode
How to Calculate the Least Common Multiple
How to Determine Less Than & Greater Than in Fractions

Dont Go!

We Have More Great Sciencing Articles!