Write variable expressions: word problems

Learning Objectives Identify keywords that indicate specific mathematical operations. Define variables to represent unknown quantities in word problems. Translate simple word phrases into algebraic expressions. Translate multi-step word problems into algebraic expressions. Distinguish between an expression and an equation. Apply the correct order of operations when writing multi-step expressions. Ever wonder how mathematicians turn everyday language into powerful math tools? 🧐 Let's unlock the secret to translating words into algebraic expressions! In this lesson, you'll learn how to read word problems and convert them into mathematical expressions using variables, numbers, and operation symbols. This skill is fundamental for solving more complex problems in alge...

TermDefinitionExample VariableA symbol, usually a letter (like x, y, or n), that represents an unknown or changing quantity in a mathematical expression.In the phrase 'a number increased by five', 'a number' can be represented by the variable 'x'. ExpressionA mathematical phrase that contains numbers, variables, and operation symbols (like +, -, ×, ÷), but does NOT contain an equality sign (=).3x + 7 is an expression. It does not state that it equals something. ConstantA number in an expression whose value does not change.In the expression '2n - 8', the number '8' is a constant. CoefficientThe numerical factor that multiplies a variable in an algebraic term.In the expression '5y + 10', the number '5' is the coefficient...

Addition Keywords Keywords: sum, plus, increased by, more than, total of, added to. Rule: $a + b$ When you see these words, it means you should add the quantities together. Be careful with 'more than' – the number being added comes after the variable or other quantity. Subtraction Keywords Keywords: difference, minus, decreased by, less than, subtracted from, take away. Rule: $a - b$ These words indicate subtraction. Pay close attention to the order for 'less than' and 'subtracted from' – the first quantity mentioned in the expression often comes second in the written form (e.g., '5 less than a number' is $x - 5$). Multiplication Keywords Keywords: product, times, multiplied by, of, twice, double, triple. Rule: $a \cdot b$ or $ab...