91Ó°ÊÓ

Arithmetic expressions are combinations of numbers and operations like addition, subtraction, multiplication, and division. These expressions reveal the relationships between numbers and how we can manipulate them to find values. To work with arithmetic expressions effectively, it's important to understand and follow the **order of operations**. This set of rules ensures that we perform calculations in a consistent and correct manner. In the exercise provided, the expression \(25 - 11 \cdot 2 + 1\) involves subtraction, multiplication, and addition.
The key to solving such expressions is to recognize and correctly apply each operation while obeying the order of operations.

• Follow **PEMDAS/BODMAS**: Parentheses/Brackets, Exponents/Orders, Multiplication and Division, Addition and Subtraction.
• Always address multiplication and division before moving on to addition and subtraction, unless parentheses indicate a different order.

This keeps calculations clear and error-free.

In arithmetic expressions, multiplication and addition are basic yet crucial operations. Understanding their role is vital for solving expressions correctly.
In any expression, multiplication should be performed before addition, following the order of operations rules. This ensures that we don't mistakenly alter the expression's intended value.
Let's break down their specific roles:
* **Multiplication**: When multiple numbers are multiplied together, it is equivalent to adding one number repeatedly. For example, \(11 \cdot 2 = 22\) means adding 11 two times.
* **Addition**: Adding is combining two numbers into a single sum, like \(3 + 1 = 4\).
By tackling multiplication first, as we did with \(11 \cdot 2\), we respect the priority given by the order of operations. Then we can move on to addition, ensuring our final result is accurate.

Left-to-right calculation ensures we execute operations in the correct sequence when different ones have the same precedence level, such as addition and subtraction.
Once any multiplication or division in an expression is finished, you deal with addition and subtraction as they appear from left to right. For example, in our expression \(25 - 22 + 1\):

• Start with the subtraction: \(25 - 22\), which equals \(3\).
• Next, proceed to the addition: \(3 + 1\), resulting in \(4\).

By moving left to right, we maintain the numerical relationships intended by the original expression. This approach allows calculations to be straightforward and ensures each part of the expression is handled precisely, leading to a correct and clear final result.