Middle School Grade 1 mathematics
Step 4 covers Middle School Grade 1. All 18 activities for this grade band are now translated into English, with the same quizzes and best-score tracking as the Korean site.
🔢 Number & operations
Prime Number Explorer
Click through the Sieve of Eratosthenes and watch multiples get crossed out until only primes remain.
Open English lesson → 🌳Prime Factor Tree Lab
Split a number into a tree of factors, down to nothing but primes.
Open English lesson → 📐Exponents & Laws of Exponents Bridge Lab
See what an exponent means, then discover why multiplying same-base exponents adds them.
Open English lesson → 🌡️Integers & Number Line Lab
Watch an arrow move along a number line to make sense of adding and subtracting positives and negatives.
Open English lesson → 🌡️Integer Multiplication & Division Sign Rules Lab
Decrease a multiplier one step at a time and watch the sign-flipping pattern reveal itself.
Open English lesson → 🧮Divisor Count Formula Lab
Explore the formula that lets you calculate the number of divisors directly from prime factorization, without counting the divisors one by one.
Open English lesson → ✖️Negative Multiplication Pattern Lab
Follow the pattern and discover why multiplying a negative number by a negative number gives a positive result.
Open English lesson → 🌀Ulam Prime Spiral Lab
Arrange numbers in a spiral starting from 1 and leave only primes as dots to reveal a striking pattern of primes clustering along diagonals.
Open English lesson → 0️⃣Zero & Negative Exponents Lab
Follow the pattern as an exponent decreases one step at a time and see why a⁰=1 and negative exponents are defined the way they are.
Open English lesson →📈 Patterns & relationships
Equation Balance Lab
Keep a balance scale level by applying the same operation to both sides, and solve for x.
Open English lesson → ⇄Direct & Inverse Proportion Lab
Switch between y=kx and y=k/x and compare how differently the graphs behave.
Open English lesson → 🕐Clock Hand Angle Lab
An interactive lab where you can calculate the angle formed by the hour and minute hands from a given time, and even find the exact times when the two hands overlap.
Open English lesson → 🚗Speed, Distance & Time Graph Lab
When speed is constant, distance is directly proportional to time; for a fixed distance, time is inversely proportional to speed. Explore both relationships with graphs.
Open English lesson →📐 Shape & measurement
Parallel Lines & Angles Lab
Slice two parallel lines with a transversal and find the vertical, corresponding, and alternate angles.
Open English lesson → ≅Triangle Congruence Conditions Lab
Enter values for SSS, SAS, ASA, RHS, or RHA and watch two triangles overlap perfectly.
Open English lesson → △Polygon Interior Angle Sum Lab
Watch a polygon split into triangles from one vertex to see where (n−2)×180° comes from.
Open English lesson → 🔺Polygon Exterior Angle Sum Lab
Change the number of sides and confirm the exterior angle sum always stays 360°.
Open English lesson → 🧊Cylinder & Cone Volume Lab
Match a cylinder and cone's base and height and confirm the volume ratio is always exactly 3 to 1.
Open English lesson → 🔪Solid Cross-Sections Lab
Rotate and slice cones, cubes, prisms, and more in 3D to see how the cross-section shape changes.
Open English lesson → 🥧Sector Arc Length and Area Lab
Change the radius and central angle and see for yourself how a sector's arc length and area are determined by its proportion of the whole circle.
Open English lesson → 🔺Triangle Inequality Lab
Change the three side lengths with sliders and see exactly when a triangle can and cannot be formed.
Open English lesson → ⚽Truncated Icosahedron Lab
Rotate a truncated icosahedron made of 20 hexagons and 12 pentagons and verify Euler's formula.
Open English lesson →📊 Data
Mean, Median & Mode Lab
Type in your own numbers and see how the mean, median, and mode each shift.
Open English lesson → 📶Frequency Table Lab
Adjust the class width and watch raw data organize itself into a frequency table and histogram.
Open English lesson → ➗Relative Frequency Lab
Compare two different-sized classes fairly by switching from raw counts to relative frequency.
Open English lesson → 🎚️Representative Value Comparison Lab
Change one student's value to an extreme and see how the mean, median, and mode respond. The mean is sensitive to outliers, while the median is much less affected.
Open English lesson →