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Fast Stacks


Instructions

Build each tower to reach its target height. Be careful: one block too many makes the tower topple and adds 2 seconds to your time.


Click STACK to add a block. You can also press the space bar or tap a tower.


As you progress, you'll encounter challenges where you can enter an equation to build the towers. Type your rule after y = and press Build.


Use the table of values to study the relationship between each tower's position and height. After building, check the results to see which values match your rule.


Try to beat the time goal and earn three stars. A correct rule on your first try earns three stars, regardless of how long it takes to type.


Play again to get new numbers and fresh challenges every time.

Introduction

Fast Stacks is a free algebra game where students build towers, race against the clock, and discover the pattern behind linear equations. What begins as a speed challenge gradually becomes a puzzle about slope, y-intercept, and rate of change. Across 26 levels in 7 worlds, students work with tables of values, coordinate points, and graphs to develop and apply equations in slope-intercept form, y = mx + b.

WHY THIS GAME MATTERS

Why students love this game:

  • The early levels feel like a fast-paced arcade challenge

  • Towers grow right before their eye

  • Discovering the pattern behind an entire skyline feels rewarding

  • Immediate feedback shows which values match their rule

  • Stars and time goals encourage students to improve

  • New numbers make every attempt different

  • A global leaderboard gives students a score to chase

Skills students build:

  • Writing linear equations in slope-intercept form

  • Identifying slope and y-intercept

  • Finding rates of change

  • Working with positive and negative slopes

  • Understanding fractional slopes

  • Writing equations from tables and coordinate points

  • Connecting visual, numerical, and algebraic representations

Great For

This free algebra game is especially useful for:

  • Algebra 1

  • Grades 8–9

  • Grades 7–8 enrichment and introduction to linear relationships

  • Slope-intercept form

  • Finding slope and y-intercept

  • Rate of change

  • Writing equations from tables

  • Writing equations from coordinate points

  • Graphing linear relationships

  • Linear equations review

  • Math warm-ups

  • Math stations

  • Early finishers

  • Independent practice

  • Review before a test

Accessibility Matters

Fast Stacks is designed to support students using different ways of interacting with the game.


Accessibility features include:

  • Keyboard support

  • Screen reader support

  • Reduced-motion preference support

  • Browser-based play without requiring installation

  • Compatibility with Chromebooks

  • Compatibility with laptops and tablets


Students can use the keyboard to interact with the game, while reduced-motion support helps accommodate those who prefer less animation.

KEEP THE LEARNING GOING

Try more free math games from When Math Happens:

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