- A Basic Rule
- Addition and Subtraction of Fractions
Inside Collection (Textbook): Fundamentals of Mathematics
Summary: This module is from Fundamentals of Mathematics by Denny Burzynski and Wade Ellis, Jr. This module discusses how to add and subtract fractions with unlike denominators. By the end of the module students should be able to add and subtract fractions with unlike denominators.
There is a basic rule that must be followed when adding or subtracting fractions.
Fractions can only be added or subtracted conveniently if they have like denominators.
To see why this rule makes sense, let's consider the problem of adding a quarter and a dime.
Now,
In order to combine a quarter and a dime to produce 35¢, we convert them to quantities of the same denomination.
Same denomination → same denominator
In (Reference), we examined the least common multiple (LCM) of a collection of numbers. If these numbers are used as denominators of fractions, we call the least common multiple, the least common denominator (LCD).
To add or subtract fractions having unlike denominators, convert each fraction to an equivalent fraction having as a denominator the least common denominator ( LCD) of the original denominators.
Find the following sums and differences.
Write each of the original fractions as a new, equivalent fraction having the common denominator 12.
To find a new numerator, we divide the original denominator into the LCD. Since the original denominator is being multiplied by this quotient, we must multiply the original numerator by this quotient.
Write each of the original fractions as a new, equivalent fraction having the common denominator 6.
To find a new numerator, we divide the original denominator into the LCD. Since the original denominator is being multiplied by this quotient, we must multiply the original numerator by this quotient.
Find the following sums and differences.
A most basic rule of arithmetic states that two fractions may be added or subtracted conveniently only if they have
.
The same denominator
For the following problems, find the sums and differences.
A morning trip from San Francisco to Los Angeles took
At the beginning of the week, Starlight Publishing Company's stock was selling for
A recipe for fruit punch calls for
The side of a particular type of box measures
No; 3 boxes add up to
Four resistors,
A copper pipe has an inside diameter of
No pipe at all; inside diameter is greater than outside diameter
The probability of an event was originally thought to be
((Reference)) Find the difference between 867 and 418.
449
((Reference)) Is 81,147 divisible by 3?
((Reference)) Find the LCM of 11, 15, and 20.
660
((Reference)) Find
((Reference)) Find the value of
"Used as supplemental materials for developmental math courses."