Erick Lee
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theericklee.bsky.social
Erick Lee
@theericklee.bsky.social
700 followers 410 following 320 posts
High School Math Teacher | Desmos Fellow | Nova Scotia Math Teachers Assn President. #ITeachMath. I occasionally blog about math at https://pbbmath.weebly.com/
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Reposted by Erick Lee
samjshah.bsky.social
Day 5 of the math art class I’m teaching is complete. Today involved finishing up the stained glass window pieces and doing more hitomezashi stitching.
#mtbos #mathart
January 29, 2026 at 1:37 AM
Reposted by Erick Lee
nathanday.bsky.social
I'd consider these to all be in the realm of Different Surface Same Deep, I reckon.

Some more available here:
interwovenmaths.com/daydream-int...
and here: interwovenmaths.com/making-conne...
A selection of 6 questions using proportional reasoning in different contexts with the same numbers. A prompt saying 'Which is the odd one out?' A selection of 6 questions using linear relationships in different contexts with the same numbers. A prompt saying 'Change each question to make the answer 43.' A selection of 6 questions involving reciprocals in different contexts with the same numbers. A selection of 6 questions involving manipulating a given multiplication in different contexts.
January 28, 2026 at 10:37 PM
Reposted by Erick Lee
jsandford.bsky.social
Here's a few of my favorite activities to engage middle school mathers. Check 'em out!

docs.google.com/presentation...

#iteachmath
January 27, 2026 at 4:31 PM
Reposted by Erick Lee
johngolden.bsky.social
via my favorite librarian www.dear-data.com/theproject pretty amazing #mathart #dataviz project
THE PROJECT — Dear Data
www.dear-data.com
January 19, 2026 at 7:07 PM
Reposted by Erick Lee
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different factors of 270 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 270 in a 3 by 3 grid. The numbers in the top row add to 37. The numbers in the middle row add to 195. The numbers in the bottom row add to 22. The numbers in the left column add to 62. The numbers in the middle column add to 183. The numbers in the right column add to 9.
January 26, 2026 at 3:44 PM
Reposted by Erick Lee
howiehua.bsky.social
Be stronger with mental multiplication by thinking about a rectangle
January 25, 2026 at 6:37 PM
Reposted by Erick Lee
davidpetro314.bsky.social
New Post] Ontario Math Links - My favourite #math related links from this week:

ontariomath.blogspot.com/2026/01/math...

links and help from @tbrzezinski.bsky.social @howiehua.bsky.social @benjamindickman.bsky.social @curiouspolymath.bsky.social and more #MathChat #MTBoS #iTeachMath
January 25, 2026 at 4:55 PM
Reposted by Erick Lee
stevemaths.bsky.social
Here's our Friday #OCRMathsPuzzle.

Find the exact area of the shaded region of the diagram.

The shaded region of the square is outside of the circle. The 2 shaded regions of the circle are outside the square.

#UKMathsChat #MathsToday #Geometry #RecreationalMath
@cambridgeocr.bsky.social
Diagram shows an overlapping square and circle on a graph: Centre of circle is at the origin (0,0), The side lengths of the square are equal to the diameter of the circle. Find the exact area of the shaded region of the diagram. The points of intersection are at (-3,4), (-3,-4) and (3,-4). The region of the square that is shaded is outside of the circle. The region of the circle that is shaded is outside the square.
January 23, 2026 at 10:59 AM
Reposted by Erick Lee
studymaths.bsky.social
I think this could be a nice task to bring together Area, Perimeter, Pythagoras and Inverse functions.

With the main idea that functions are meant to do something useful with an input!
A screenshot of four functions, a picture of a square and the command "Match each function to what it does." The four functions: a) Calculate the area of a square given its diagonal. b) Calculate the diagonal of a square given its area. c) Calculate the perimeter of a square given its area. d) Calculate the area of a square given its perimeter.
January 23, 2026 at 8:00 AM
Reposted by Erick Lee
neechmaths.bsky.social
In #MathsToday #AlevelMaths perfected their differentiation skills which included dominoes, they are very much ready to move on to some applications next week.
Completed differentiation dominoes activity
January 21, 2026 at 8:47 PM
Reposted by Erick Lee
ukmathstrust.bsky.social
Problem of the Week 156!

Please do not comment the solution so others can work it out too. Instead, like this post or comment a thumbs up if you think you have the correct answer!

The solution will be posted in the comments on Thursday afternoon.

#Problem #UKMT #Maths
January 20, 2026 at 8:00 AM
Reposted by Erick Lee
davidpetro314.bsky.social
[New Post] Ontario Math Links - My favourite #math related links from this week:

ontariomath.blogspot.com/2026/01/math...

links and help from @theericklee.bsky.social @momath.bsky.social @howiehua.bsky.social @afetter29.bsky.social @mathowitz.bsky.social & more #MathChat #MTBoS #iTeachMath
January 18, 2026 at 4:35 PM
theericklee.bsky.social
Monthly Mind-benders puzzles from Peter Winkler and @3blue1brown.com! A great team together with @momath.bsky.social. The first puzzle is out now. #ITeachMath momath.org/mindbenders/
momath.org
January 16, 2026 at 7:44 PM
theericklee.bsky.social
My son is practicing Pythagorean Theorem at school so he is squaring lots of two digit numbers. Showed him the “close together method” I learned recently from Arthur Benjamin’s book The Magic of Math. I’ve been using this method lots now that I know why/when it works.
Check if numbers are Pythagorean triples The close together method of multiplication. The Magic of Math by Arthur Benjamin.
January 15, 2026 at 11:40 PM
theericklee.bsky.social
Had a wonderful evening at MoMath for the 2025 Rosenthal Prize presentation. It was great to meet everyone and to chat about the intersection of math, magic and music. @momath.bsky.social
Museum of Mathematics in New York City. Rosenthal prize winners for 2025
January 15, 2026 at 4:09 AM
theericklee.bsky.social
Haven’t played Scrabble in years but my son has gotten in to it. I think Wordle has made me a better player. It’s really a math game disguised as a word game.
A game of Scrabble in progress.
January 14, 2026 at 7:57 PM
Reposted by Erick Lee
davidpetro314.bsky.social
[New Post] Ontario Math Links - My favourite #math related links from this week:

ontariomath.blogspot.com/2026/01/math...

Links and help from @karencampe.bsky.social @tbrzezinski.bsky.social @amplifyeducation.bsky.social @ahestenes.bsky.social @priy45hah.bsky.social
#MathChat #MTBoS #iTeachMath
Math Links for Week Ending Jan 9th, 2025
Featured Links I have been a Desmos Fellow (now Amplify Fellow) since 2018 and it has given me resources, insight and inspiration. And don't...
ontariomath.blogspot.com
January 11, 2026 at 5:46 PM
Reposted by Erick Lee
karencampe.bsky.social
Let's do #ProblemSolving Sunday! Here is today's calendar problem... share how you thought about this one (or any others from this past week of the January Calendar of problems. Link below)
#iTeachMath #MTBoS #MathSky #RecreationalMath #MathsToday
A flag design is shown. A cross is symmetrically placed in the flag such that the same size rectangle is located in each corner. All four arms are the same width. Supposed that the flag measures 3 meters high by 4 meters across. How wide should the arms of the cross be so that it makes up half the area of the flag?
January 11, 2026 at 3:30 PM
Reposted by Erick Lee
drfrostresource.bsky.social
🧮 UKMT Intermediate Maths Challenge

The IMC takes place on Wednesday 28 January 2026.

All papers up to and including 2025 are now available on @drfrostmaths.bsky.social - ideal for classroom practice and independent preparation.

👉 Access the papers here ⬇️
buff.ly/08WWOBO
January 11, 2026 at 9:30 AM
Reposted by Erick Lee
studymaths.bsky.social
When introducing the idea of Completing the Square, I find numerical examples in base ten can be a helpful stepping stone for pupils.

Bridging the gap between numbers and algebra.
A visual representation of completing the square with Dienes and Algebra Tiles, comparing 146 = (10 + 2)² + 2 with x² + 4x + 6 = (x + 2)² + 2.
January 10, 2026 at 10:35 AM
Reposted by Erick Lee
amplifyeducation.bsky.social
🥶 A fun way to beat winter brain freeze.

In this free Grade 8 lesson, students use reasoning to solve systems of equations through fun, puzzle-style challenges—featuring snowy clues, frozen boots, and more.

❄️ Give it a try: go.amplify.com/48FBL3U.
Promotional image for "Frosty Figures," a grade 8 math activity from Amplify Classroom that encourages students to solve engaging puzzles and learn reasoning through systems of equations. The illustration features a whimsical character resembling a cat within a frosty, starry setting on a digital device screen.
January 9, 2026 at 6:25 PM
Reposted by Erick Lee
pwharris.bsky.social
It's time for #MathStratChat!

Rules: post your favorite or a clever solution! It's also fun to comment on other's strategies.

Tell us about your reasoning.

Like/Share so others can see!

#MathIsFigureOutAble #MathsStratChat #MTBoS #ITeachMath #MathEd
January 8, 2026 at 1:46 AM
Reposted by Erick Lee
jsandford.bsky.social
Click on the link below to check out my latest newsletter:

drive.google.com/file/d/1MHZp...

Hope you like it!
#iteachmath
January 7, 2026 at 12:04 AM
Reposted by Erick Lee
ukmathstrust.bsky.social
Problem of the Week 154!

Please do not comment the solution so others can work it out too. Instead, like this post or comment a thumbs up if you think you have the correct answer!

The solution will be posted in the comments on Thursday afternoon.

#Problem #UKMT #Maths
January 6, 2026 at 8:00 AM
theericklee.bsky.social
Playing one last game of Letters to Santa before putting it away until next December. I am loosing most egregiously.
A game of Letters to Santa.
January 3, 2026 at 1:31 AM