Combined operations
Operations with natural numbers II
 

1. Combined operations.

This is an expression formed by numbers in different operations and grouped in different ways - by means of brackets, square brackets and braces {curly brackets}.
To solve combined operations we must master all the operations studied above.

- The aim of using brackets is to join or to group everything that is between them.

- Multiplication signs have priority over addition and subtraction signs, that is, when two numbers are joined by the multiplication sign they are inseparable. But if they are linked by the addition or subtraction sign, they can be separated.

- We must know the properties of the operations so that we don't do anything wrong.

- To add up or subtract two numbers they must be separated. We cannot add up two numbers if one of them is linked to another expression by means of a multiplication sign.

- Combined operations are solved in several steps. What is not solved in one step must be copied as it was, without omitting it or changing its position.
 
- So, before starting to solve combined operations, we must evaluate the expression and plan a strategy to implement: what we are going to do before and after.

- As a general rule, it is best to solve what is inside the brackets first, then do the multiplications and finally do the remaining additions.

  Esta unidad interactiva requiere la máquina virtual de Java J2RE.

You must type a number in the box below the window. This number must be the result of a part of the expression.

You must do it successively, step by step. In order to do this, you must delete the previous number.
When you type the right number it will appear in the window. If the typed number is not correct it will not appear.

It is not about  finding the final result directly.

When you click on Init a new expression of combined operations will appear. Solve some of them.

 


         
           
  Eduardo Barbero Corral
 
Spanish Ministry of Education. Year 2007
 
 

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