1_1 Evaluating Expressions

Example 1

Evaluate the expression (3+5)*4.
Write these steps: Think these reasons:
Write the given expression. (3+5)*4 The first step is to write the given expression. Now we start to evaluate the expression. First we look for a multiplication. But there is nothing to multiply. Then we search from left to right for a division. But there is nothing to devide. Then we search for an addition and discover that one can add 3 and 5. Therefore the next step is an addition.
Add. = 8*4 Next we evaluate the multiplication.
Multiply. = 32 Finally, we indicate that this is the answer.
Underline the answer.




Example 2

Evaluate the expression 30-10/2.
Write these steps: Think these reasons:
Write the given expression. 30-10/2 The first step is to write the given expression. Now we start to evaluate the expression. There is nothing to multiply. But one can divide 10 by 2. Therefore the next operation is a division.
Divide. = 30-5 Next, evaluate the subtraction.
Subtract. = 25 Finally, we indicate that this is the answer.
Underline the answer.




Example 3

Evaluate the expression 30-10+5-2.
Write these steps: Think these reasons:
Write the given expression. 30-10+5-2 The first step is to write the given expression. Now we start to evaluate the expression. There is nothing to multiply or divide. Additions and subtractions with more than one term are evaluated from left to right. Therefore the next step is a subtraction.
Subtract. = 20+5-2 There is nothing to multiply or divide. Additions and subtractions with more than one term are evaluated from left to right. Therefore the next step is an addition.
Add. = 25-2 Next, evaluate the subtraction.
Subtract. = 23 Finally, indicate that this is the answer.
Underline the answer.




Example 4

Evaluate the expression .

Write these steps: Think these reasons:
Write the given expression. The first step is to write the given expression. Now we start to evaluate the expression. We first search the numerator for a multiplication from left to right. The next step is the multiplication of 3 and 4.
Multiply. We first search the numerator nad the denominator for a multiplication from left to right. But there is nothing to multiply. Then we search for a division and discover that one can divide 4 by 2. Therefore the next step is a division.
Divide. There is nothing to multiply and divide. But one can add 2 and 12. Therefore the next step is an addition.
Add. There is nothing to multiply, divide, and add. But one can subtract 2 from 9. Therefore the next step is a subtraction.
Subtract. Next, evaluate the division.
Divide. Finally, indicate that this is the answer.
Underline the answer.

Algebra Section 1_1
Exercises


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