Definition: An algebraic expression is a mathematical phrase that combines numbers, variables, and operation symbols, but has no equal sign.
What is an algebraic expression?
An expression is a phrase of math, not a complete sentence. It can include numbers, variables, and operations such as 3x + 7 or 5(n – 2). Because it has no equal sign, it cannot be true or false.
What are its parts?
Take 8y + 3z – 11. The terms are 8y, 3z, and -11. The numbers multiplying variables are coefficients, here 8 and 3. The term -11 is a constant, since it never changes.
How do you translate words into expressions?
- Seven more than a number: n + 7
- Twice a number decreased by five: 2n – 5
- The quotient of a number and four: n / 4
How is it different from an equation?
An equation says two expressions are equal and can be solved. An expression can only be simplified or evaluated. Writing 3x + 7 = 22 turns the expression into an equation.
What is a typical error?
Translating less than backwards. Six less than a number is n – 6, not 6 – n.
Example: Mathbot buys 4 batteries at b dollars each plus a 3 dollar bag: 4b + 3.