Algebra 1 Basic

Evaluating Expressions

Enter any algebraic expression and assign values to each variable. The calculator walks you through every substitution and simplification step so you can see exactly how the final answer is reached.

Supports multi-variable expressions
Shows substitution step by step
Live
Input
Use ^ for powers, e.g. x^2. Write coefficients right before variables: 2x.
Type an expression above…
Result
Enter an expression and variable values, then click Evaluate Expression to see the answer.
Final Answer
Original Expression
After Substitution
Step-by-Step Solution
What Does "Evaluating" Mean?

To evaluate an expression means to find its numerical value by replacing every variable with a given number, then computing the result using order of operations.

Think of a variable as a blank placeholder. Evaluating is like filling in the blank with a specific number and then calculating.

For example, to evaluate 3x + 2 when x = 5:

3(5) + 2 = 15 + 2 = 17
Always substitute first, then simplify using PEMDAS/BODMAS order.
Why Parentheses Matter

When you substitute a value — especially a negative number — wrapping it in parentheses prevents sign errors.

Consider when x = −3:

(-3)² = 9 ✓ vs -3² = −9 ✗

The parentheses make it clear that the negative sign is part of the base being squared, not a separate negative applied to 9.

This calculator always wraps substituted values in parentheses so the math stays correct — and so you can see this habit modelled in every step.

  • Substitute all variables simultaneously
  • Use parentheses around negative values
  • Follow PEMDAS after substituting

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