Writing Expressions

An expression is a combination of numbers, variables, and operators (such as +, -, ×, ÷) that represents a value.

Adding a number to a variable means to increase the value of the variable by that number. For example, '7 more than a number b' is written as b + 7.

When something is 'subtracted from' a variable, it means you take that number away from the variable. For example, '13 subtracted from t' is written as t - 13.

A coefficient is a number that is multiplied by a variable. For example, in 3x, 3 is the coefficient.

A constant is a fixed value that does not change. For example, in the expression 2x + 7, 7 is the constant.

A variable is a symbol that represents an unknown value, while a constant is a specific value that does not change.

Evaluating an expression means to calculate its value by substituting the variables with specific numbers.

The sum of a number x and 5 is written as x + 5.

The result of multiplying a number by a variable is called a term. For example, 4x is a term.