Evaluating Expressions with Variables

A variable is a symbol, often a letter, that represents a number that can change or vary.

To evaluate an expression means to calculate its value by substituting variables with numbers and performing the operations.

If a total amount is represented by T and there are n friends, the expression is $$\frac{T}{n}$$ .

If quantity A is more than quantity B by a certain amount, it can be represented as A = B + amount.

The cat's weight can be expressed as $$r + 6$$ .

The dog's weight is expressed as $$3 \times (r + 6)$$ .

The first step is to isolate the variable on one side of the equation.

To simplify an expression means to reduce it to its simplest form by combining like terms and performing operations.

To find the total of two amounts, you add them together: Total = Amount1 + Amount2.

Parentheses indicate which operations should be performed first in an expression.