# Pre-Algebra : Addition and Subtraction

## Example Questions

### Example Question #11 : Addition And Subtraction

Perform the indicated mathematical operations:

Explanation:

In this problem we have two different types of terms. Those with x and without it. These two cannot be combined, but the fractions can. First we find a common denominator by multiplying one fraction by a number over itself that gives common denominators.

Now subtract the fractions:

Since the 5 term does not have an x we cannot combine the two.

### Example Question #12 : Addition And Subtraction

Explanation:

This is the ones digit of the final answer.

The ones digit is the tens digit of the final answer.

Since there is a tens digit in this number, carry over the tens digit to the next calculation.

Add the hundreds digit with the carry over.

This number will represent the thousands and hundreds digit.

Combine the numbers.

### Example Question #12 : Addition And Subtraction

Solve:

Explanation:

Solve the inside of the parentheses. Then remove all the parentheses by distributing the negative signs.

### Example Question #13 : Addition And Subtraction

Compute:

Explanation:

Solve  term by term.

### Example Question #15 : Addition And Subtraction

Explanation:

The ones digit is the ones digit of the final answer.  Since there is a one in the tens digit, this is the carry over for the next calculation.

Add the tens digit with the carryover.

Combine all the numbers.  The answer is .

### Example Question #16 : Addition And Subtraction

Solve:

Explanation:

Subtract the ones digit.  Borrow a one from the tens digit.

After borrowing a one from the , the tens digit of  will be .

Subtract the tens digit.

### Example Question #14 : Addition And Subtraction

Explanation:

Combine the two digits.

### Example Question #15 : Addition And Subtraction

Subtract:

Explanation:

The ones digit cannot be subtracted as is.  We cannot borrow a one from the tens digit.  Borrow a one from the  of both the tens and the hundreds digit of .

This is the ones digit of the final answer.

Because a one was borrowed, the tens digit of  will be come a , and the hundreds digit will become zero.  Subtract the tens digits.

### Example Question #16 : Addition And Subtraction

Explanation:

Simplify the parentheses.

A positive and a negative sign will result in a negative sign.

Explanation: