In order to add the fractions, we will need a common denominator.

Notice that the largest denominator is divisible by seven.  We can change just the first fraction to the least common denominator.

Rewrite the fraction.

Reduce this fraction by writing out the common factors of the numerator and denominator.

The answer is:  

The denominators are not common.  Convert the denominators to a least common denominator.

To obtain the LCD, we can multiply four times three.

This value is the least possible value divisible by four and three.

Convert the fractions.  Multiply the numerators by what was multiplied on the denominator to get the LCD.

Simplify the fractions and add the numerators.  The denominator stays the same.

Forty three goes into twelve three times.  The remainder is seven, which can be written as seven-twelves.

The answer is:  

In order to add these fractions, we will need a common denominator.  Notice that the least common denominator is nine since it's the least number divisible by both denominators.

Convert the second fraction to the correct denominator.

Simplify the fractions.

The answer is:  

The least common denominator is 12.  Convert the first fraction to this denominator in order to subtract the numerators.  The denominators will remain the same.

Simplify the fractions.

The answer is:  

To subtract the fractions, we will need to find the least common denominator.

Write out the factors for both denominators.

Multiply four by 15 to get the least common denominator.

The least common denominator is .

Convert both fractions.

The answer is:  

Determine the least common denominator.  Expand the factors for each denominator.

The least common denominator is .

Add the numerators.

The answer is:  

In order to subtract these fractions, we will need to convert the first fraction with a common denominator of 24.  Multiply the top and bottom by four.

Simplify the numerator by combining like-terms.

Simplify the fraction.

The answer is:  

In order to add or subtract the numerator, we will need common denominators.

The least common denominator is 24.

Convert the first fraction to the common denominator by multiplying both the top and bottom by 8.

Subtract the numerator only.  The denominator will remain the same.

The answer is:  

In order to add the fractions, we will need a common denominator.  Write out some of the factors for each of the denominators:

Notice that since  is a common denominator, we will need to change the fractions with a denominator of .

Simplify the fractions.

Reduce the fraction.

The answer is:  

In order to subtract, convert the second fraction to an improper fraction.

Multiply the denominator by the whole number and add the numerator.  The denominator stays the same.

Multiply the two denominators together in order to obtain the least common denominator. Convert the fractions and simplify.

The answer is: