Grade 8 mathematics
Step 5 covers Grade 8 (middle school). All 13 activities for this grade band are now translated into English, with the same quizzes and best-score tracking as the Korean site.
🔢 Number & operations
Rational Numbers & Repeating Decimals Lab
Guess ahead of time whether a fraction will be terminating or repeating, then check with the actual long division.
Open English lesson → 🔄Repeating Decimals Lab
Why does dividing out a fraction like 1/3 or 1/7 repeat forever? Explore the repetend length and converting back to a fraction.
Open English lesson →📈 Functions & graphs
Linear Function Graph Lab
Adjust the slope and y-intercept with sliders and watch the line move in real time.
Open English lesson → 🧮Working with Expressions Lab (Laws of Exponents & Like Terms)
Check the laws of exponents with sliders, and group scattered terms into like terms to simplify a polynomial.
Open English lesson → 📏Linear Inequalities & Systems of Equations Lab
See why the inequality sign flips when you multiply or divide by a negative, and find a system's solution where two lines cross.
Open English lesson → 📍Line Intersection Lab
The solution to a system of equations is the point where two lines intersect. Look at the graph and find the coordinates of the intersection point.
Open English lesson → 🔗Linear Functions and Linear Equations: Relationship Lab
See for yourself that the intersection of two linear-function graphs is the solution to the corresponding system of linear equations.
Open English lesson → 🛹Ramp Slope Lab
Adjust the horizontal run and vertical rise to build a ramp, and see that its slope is the same as the slope a of the linear function y=ax.
Open English lesson →📐 Shape & geometry
Pythagorean Theorem Lab
Draw squares on the three sides of a right triangle and see a²+b²=c² with your own eyes.
Open English lesson → 📏Distance Between Two Points on a Coordinate Plane Lab
Move two points with sliders and see how the Pythagorean theorem gives you the exact distance between them.
Open English lesson → ⧉Similarity & Congruence Lab
Adjust the scale factor and watch a shape grow or shrink, and see how the ratio of areas and perimeters changes.
Open English lesson → ◇Properties of Triangles & Quadrilaterals Lab
Reshape an isosceles triangle and several quadrilaterals with sliders and see their side, angle, and diagonal properties never break down.
Open English lesson → 📏Parallel Lines and Segment Ratios Lab
Draw a line parallel to the base of a triangle and use the slider to explore the ratios of the resulting segment lengths.
Open English lesson → 📐Pythagorean Triple Lab
Explore Euclid's formula and generate infinitely many Pythagorean triples such as 3-4-5 using just two numbers, m and n.
Open English lesson → 📦Similarity Ratio, Area Ratio, and Volume Ratio Lab
See directly with 3D shapes that when the similarity ratio is k, area changes by k² and volume by k³.
Open English lesson → 📐Triangle Circumcenter & Incenter Lab
Change the shape of the triangle to see where the circumcenter and incenter appear and what properties each one has.
Open English lesson → ⚖️Triangle Centroid Lab
Reshape the triangle and confirm that the centroid, where the three medians meet, always divides each median in a 2:1 ratio.
Open English lesson →📊 Probability & statistics