## Friday, July 4, 2014

### Numerical expressions - order of operations and solved examples

Numerical expressions are essential for knowledge of maths, and very important in its use in every day. To help you study maths, here you will learn what are numerical expressions and how to calculate numerical expressions.

Numerical expressions

A numerical expression is a way of expressing reasoning in a problem and another way to represent a number. Any numerical expression represents a value. But you perceive better checking the following example:

John went to the supermarket with 10 dollars and bought two cans of mushrooms and a bag of flour. Knowing each can of mushrooms cost \$1.30 and the package flour \$1.10, indicate:

a) how much money was spent.

To solve this problem, you must use the numerical expression: 2 x 1.30 + 1.10
2 x 1.30 + 1.10 expresses the amount he spent, which is equal to \$3.70.

b) how much money is left.

To solve this problem, you must use the numerical expression: 10 - (2 x 1.30 + 1.10)
10 - (2 x 1.30 + 1.10) expresses the value that is left, which is equal to \$6.30.

How to calculate numerical expressions

To learn how to calculate numerical expressions, is critical to realize that exists a series of operations, and so, there must be rules to implement them. This rules are called order of operations. So, to calculate numerical expressions, you have to know the order of operations of numerical expressions. Below, you can find an example with the rules explained to you understand more easily.

• Order of operations

In a numerical expression, the operations are not made simply by the order in which they appear. Each type of operation has a priority, which indicates which operations must be done in the first place. Then you can check the order of operations to calculate numerical expressions.

1st Priority - Firstly, make all calculations within parentheses (these calculations must follow the rules described below).
2nd Priority - For operations, we must first make the exponents or roots.
3rd Priority – Calculate the multiplications and divisions in the order they appear.
4th Priority - Finally, calculate the additions and subtractions in the order they appear.

• Solved examples of numerical expressions

23-4 x 5 =    --- 3rd P - Make first the multiplication
= 23-20 =         --- 4th P – Make the subtraction
= 3

Now a solved example a little more complicated:

#### 1 comment:

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