Every equation is a scale. Keep it level, and the answer reveals itself.
REMEMBER: An equation is a balanced scale — whatever you do to one
side, you must do to the other. To solve px + q = r, undo the
adding first, then the multiplying. And if you divide an
inequality by a negative, the symbol flips.
Part 1 · Keep the Scale Level
Green boxes are mystery weights (x). Gold coins weigh 1 each.
Both pans weigh the same — that's what the = sign promises. Use the buttons to
make legal moves (same move, both sides) until one x stands
alone. Or press the ⚠️ button to see what happens when you cheat...
Part 2 · Graph It Right
An inequality has a whole CROWD of answers, and the number line shows them all.
Read the inequality (watch out — some need a divide-by-a-negative first!).
Choose your circle and your arrow, then Lock It In before the
reveal.
1. The circle at the boundary number:
2. The arrow (which numbers work):
Correct graphs: 0
Part 3 · The Two-Step Solver
Build any two-step equation or inequality: px + q compared to
r. The solver shows every legal move, checks its answer, runs
an estimation sanity check — and graphs the solution when it's an inequality.
Try a negative p with an inequality to see the famous flip!
Part 4 · Balance Master Quiz
Question 1 of 10Score: 0
📗 Word Box
Equation
A math sentence with an equals sign. It promises both sides have the same value — like a level scale.
Inequality
A math sentence with <, >, ≤, or ≥. Instead of one answer, it has a whole set of answers.
Solution set
ALL the numbers that make an inequality true. We show it as a shaded ray on a number line.
Inverse operations
Operations that undo each other: adding undoes subtracting; multiplying undoes dividing.
Isolate the variable
Get x alone on one side of the scale. That's the whole goal of solving.
Open circle ○
Marks a boundary number that is NOT included (used for < and >).
Closed circle ●
Marks a boundary number that IS included (used for ≤ and ≥).
Estimate
A quick rounded calculation to check if your exact answer makes sense. Your math's smoke alarm!