Erick Lee

@theericklee.bsky.social

764 Followers 459 Following

High School Math Teacher | Desmos Fellow | Nova Scotia Math Teachers Assn President. #ITeachMath. I occasionally blog about math at https://pbbmath.weebly.com/

A geometric Desmos graph depicting a Riemann sum with a Piet Mondrian abstract art aesthetic. A thick, vibrant coral-pink cubic function curve waves smoothly from left to right across the square frame. The graph is filled with a grid of rectangular blocks using a "Moon Mist" ice cream color palette: grape purple, banana yellow, bubblegum blue, and crisp white. The colorful blocks form vertical columns bounded by clean, dark teal lines, abstractly representing the calculus area approximation underneath the pink curve.
Two calculus challenges side by side, framed in rounded blue borders. On the left side, labeled Mild, a text prompt asks, A parabola is drawn inside a square. What fraction of the square is colored red? Below the text is a square containing a bright red vertical parabola whose peak touches the top edge midpoint and whose base spans the bottom corners from edge to edge. On the right side, labeled Spicy, a text prompt asks, A parabola is drawn inside a regular hexagon. What fraction of the hexagon is colored red? Below the text is a regular hexagon resting on a flat bottom edge, containing a tall red vertical parabola whose peak touches the midpoint of the top edge and whose base spans the bottom edge from corner to corner. For both challenges, the areas inside the shapes but outside the red parabolas are shaded light grey.
(Problem 1): Graph of the parabola y equals 4 minus x squared and the line y equals negative 2x plus 4. The shaded region is the area bounded between the parabola and the line, extending from x equals 0 to x equals 2, where they intersect.
Two side-by-side math problems labeled "MILD" and "SPICY" with chili pepper icons, focusing on calculus integration in the first quadrant. Left Panel (MILD): Text prompt: "Find the area in the first quadrant between the two functions." Graph details: Shows an x-y coordinate plane. A red downward-opening parabola is labeled "y = 4 - x^2". A green straight line is labeled "y = -2x + 5" and is tangent to the parabola in the first quadrant. The area between the line and the parabola, bounded by the y-axis on the left and the x-axis on the bottom, is shaded green. Right Panel (SPICY): Text prompt: "What value of a minimizes the area in the first quadrant between the parabola and its tangent line." Graph details: Shows the same red downward-opening parabola labeled "y = 4 - x^2". A blue tangent line touches the parabola at a point where the x-axis value is marked as "a" with a vertical dashed line. The region between the tangent line, the parabola, the y-axis, and the x-axis is shaded blue-green.
An online calculus practice question from mathmatize.com. The problem statement reads: "The region enclosed by y = (x^2)/4 and y = 5 - x^2 is rotated about the x-axis. Fill in the blanks to correctly compute the volume of the resulting solid:" Below the text is an incomplete integral formula: Volume = Integral from [dashed blank] to [blank] of [blank] dx At the bottom, a multiple-choice interface for "Blank 1" shows a row of selectable numerical buttons: -4, -2, -1, -1/2, 0, 1, 1/2, 2, and 4. A purple button below reads "CHECK ANSWER" with "3 attempts remain" written underneath.
An All Ten puzzle where every number is made with digits in the same order.
Students are arranging calculus domino-style cards into a long, winding chain. Each card is divided in half: one side features a definite integral formula, and the other side shows either a numerical answer or a shaded graph representing the area under a curve.
A calculus problem statement and four parts labeled A through D. The problem text reads: "Consider the region bounded by the graphs of f(x) = -x^2 + 4x + 3 and g(x) = x + 3." The individual parts are: A. Sketch the two functions on the same coordinate plane and shade the region trapped between them. B. Find the x-coordinates of the points of intersection, x = a and x = b. C. Find the maximum vertical distance between the two functions on the interval [a, b]. D. Find the exact area of the trapped region.
A team made a definite integral with a value of 22.5 (The integral of (x+2) from 0 to 5). A tie for high score.
Pythagoras drawing in the sand.
Slate pencil and board
A blue unicycle for sale on Facebook Marketplace for $25.
A classroom whiteboard with a large 10-by-10 grid numbered 1 to 100 projected onto it. Small yellow and orange sticky notes are scattered across various squares on the grid, representing spots claimed by students during a classroom challenge.
"Walt Disney's Addition and Subtraction" is a classic 1963 educational vinyl record (Disneyland Records DQ-1313). It features Jiminy Cricket teaching basic arithmetic to children through engaging narration and songs by singer-composer Rica Moore, making early math fun and memorable
All Ten puzzle solution from May 22nd, 2026
Using a temperature sensor and Microbit to record a cooling cup of tea over time.
A calculus warm-up slide featuring a math problem with text on the left and a corresponding graph on the right. The text on the left reads: "The graphs of two quadratic functions are drawn on the same axes. y = x^2 - 10x + 25 y = 3 + 6x - x^2 N and M are points on the curves, between the points of intersection. N is vertically above M. For which values of x do the two graphs intersect? Which value of x gives the maximum distance between N and M?" The graph on the right shows a Cartesian coordinate grid with the two parabolas plotted. One parabola opens upwards with its vertex at (5, 0), and the other opens downwards with its vertex at (3, 12). They intersect at two points. A vertical red dashed line is drawn at x = 3, connecting a red dot labeled "N" on the upper curve to a red dot labeled "M" on the lower curve.
A math warm-up slide titled "Time for a Debate." On the left is a right-angled triangle with a hypotenuse of 14 m and a vertical side (opposite the angle x) of 6 m. On the right, text reads: "Oh no, the sin button on your calculator is broken! What is the Weirdest way to find the value of x?" Below this is a fill-in-the-blank prompt: "My CLAIM is ______ and my WARRANT is ______."
"Each group will receive two playing cards. Answer both questions given your cards. (Jack=11, Queen=12, King=13, and Ace=14)" Below are two math problems in red rounded boxes: Box 1: "A ladder of length [Higher Card] ft is leaning against a vertical wall. The base of the ladder is being pulled away from the wall at a rate of 2 ft/s. How fast is the top of the ladder sliding down the wall when the base of the ladder is [Lower Card] feet away from the wall?" Box 2: "A water tank in the shape of an inverted cone has a height of [Higher Card] meters and a top radius of 5 m. Water is being pumped into the tank at a rate of 3 m³/min. How fast is the water level rising when the water is exactly [Lower Card] meters deep?"
hree students are working around two wooden desks pushed together. One student, on the left, is holding a long, wooden meter stick that lies horizontally across the desks. A second student, in the center, holds a flexible yellow measuring tape that extends diagonally from the top left corner of the wooden meter stick down toward the bottom right. A third student, on the right, is pointing at a small blue toy car placed near the end of the wooden meter stick. Each student’s hands are visible as they work together to take measurements. On the desks, there are also two worksheets with tables and calculations. The scene captures a moment of active, collaborative learning in a mathematics class.
Rich Task Remix title slide.
Arguing like it matters session title slide.
Running a community math night title slide.
Conference name tag for OAME 2026.
The f(x)-Files (in the style of the tv show X-Files). Below it, the tagline reads The Calculus is Out There, followed by the phrase I Want to Derive. A section titled Mission Objective states that the Bureau has intercepted fragments of data regarding unidentified functions. The mission is to use these fragments, such as slopes, concavity, and specific coordinates, to reconstruct a mystery function's graph.
A slide titled Target Answer Challenge. A green banner in the center reads Design two different math problems where the answer is 2x plus 1. Below the banner are two colored boxes. On the left is a red box titled Linear Relations with the instruction Design a problem where the goal is to determine the equation of a line. Underneath it says Think about: Constructing a problem using two coordinate points, or using a point and a given parallel or perpendicular line. On the right is a blue box titled Differential Calculus with the instruction Design a problem where the goal is to determine the derivative of a function. Underneath it says Think about: Finding the first derivative of a second-degree polynomial, or the second derivative of a third-degree polynomial.
A small gold cup trophy on a wooden base with a plaque that reads “Citadel High School Calculus Cup”
A warm up question for math class. The text at the top reads, "Match each statement to its corresponding function." The central image is a simple diagram of a square with a single diagonal line drawn from the top-left to the bottom-right corner. On the left side, there is a list of four statements: 1. Calculates the perimeter of a square given its area. 2. Calculates the area of a square given its diagonal. 3. Calculates the diagonal of a square given its area. 4. Calculates the area of a square given its perimeter. Below the square diagram, a caption states: "For each problem, x may represent a different part of the square." On the right side, there is a list of four algebraic functions: A) f(x) = (x/4)^2 B) f(x) = 4 * sqrt(x) C) f(x) = sqrt(2x) D) f(x) = x^2 / 2
Two Truths and a Lie activity for a Calculus class. The image shows Station 3, which features a coordinate plane. The graph shows a function that is a straight line with a positive slope for x less than 0. At the origin (0, 1), there is a sharp corner, and for x greater than 0, the graph curves upward (concave up). The image includes three numbers in circles—61, 19, and 38—next to three statements: Statement 1: There is an inflection point at x = 0 because the concavity of the function changes there. Statement 2: The function is continuous but not differentiable at x = 0. Statement 3: To the left of the y-axis, the second derivative f double prime of x is equal to zero. The instructions at the bottom tell students to identify which statement is the lie and explain why it is not true.
An educational graphic titled Which One Doesn’t Belong. The image asks viewers to find a reason why each of four mathematical graphs does not belong, using a provided list of calculus terms. The four graphs are arranged in a square grid. The top-left shows a periodic cosine wave oscillating between positive and negative one. The top-right shows a standard upward-opening parabola with its vertex at the origin. The bottom-left shows a rational function with a vertical asymptote at the y-axis, where both sides of the curve approach positive infinity. The bottom-right shows a cubic curve that passes through the origin and increases from the third quadrant to the first. To the left of the graphs, a list of suggested vocabulary includes Domain and Range, Continuous and Discontinuous, Differentiable, Increasing and Decreasing, Concave Up and Concave Down, and Point of Inflection.
An animated Desmos graphing calculator screen showing a smooth, continuous piecewise curve representing a roller coaster track. The track spans a coordinate plane from x=0 to x=100. Key transition points between the functions are marked and labeled with coordinates: (0, 10), (30, 40), (40, 20), (55, 5), and (100, 5). A small graphic of a red roller coaster cart smoothly animates along the entire length of the track, riding over a large hill, dropping into a valley, cresting a smaller hill, and coming to a stop at the end. The left sidebar shows organized folders titled "Roller Coaster," "Roller Coaster Derivatives/Slopes," and "Animated Cart."
A team of four students working on a math question.
An email that begins with, Dear [Teacher’s Name]…
Measuring the shadow of a metre stick on the equinox.
2018 Math Kangaroo contest for grades 7-8 on a candlelit dinner table.
The Mandelorian… this is the way.
"A 'Crack the Code' puzzle for Week 6. Five three-digit number clues are given: 342 (one number correct and well placed), 273 (nothing is correct), 165 (one number correct but wrongly placed), 853 (one number correct and well placed), and 264 (two numbers correct but wrongly placed). Three blank boxes at the bottom await the solution."
A web game to review derivative rules in Calculus class. A teal heading reads "School Physics Lab, Year 2026." Below is a paragraph of narrative text explaining that the player has been sucked into a temporal vortex and must solve calculus problems to get home. A large button at the bottom reads "START JUMP."
A horizontal box plot showing student estimations on a number line from 0 to over 500. The red box plot displays a minimum value of 71, a first quartile of 93, a median of 173, a third quartile of 270.5, and a maximum value of 520. A dashed blue vertical line marks the "Actual Value" at 350, showing that the majority of the box plot lies below the actual amount.
A clear cup filled almost to the brim with copper pennies. The pennies are stacked randomly, making it difficult to count visually and prompting an estimation challenge.
Pilot Kire-na highlighters in 5 colors.
Derivative Concentration game. Match functions to their derivatives.
Rolling the rim of a Tim Horton’s coffee cup.
Students investigate difference of powers formula.
Students doing math.
A warmup question with four questions about slope and average rate of change.
The Mathematics of Origami by Joseph O’Rourke
Rotating a circle to simplify the problem.
A math problem. Find the red area given a cirlce and square.
A finished game of Inverse.
Pentel Kerry pencil
Check if numbers are Pythagorean triples
Museum of Mathematics in New York City.
A game of Scrabble in progress.
Desmos graphing calculator
Lego bonsai tree.
A game of Letters to Santa.
Screenshot of the arcade version of the late 1980s video game Gauntlet.
Origami Sonobe unit triakis icosahedron
Sonobe Octohedron