Problems and Contests

York U|Amanda Chow - comprehensive list of Math links
Wolfram|Alpha - online calculation and computation tool for math, science, nutrition, and more
McMaster Start Coding - camps, lessons, and in-class workshops for students learning to have fun with math through coding
Khan Academy - free courses on everything from math, to science, computer programming, finances, and more.
My GRE Exam Preparation - website for students preparing for standardized tests with prep books, guides, and practice exams
Maths for kids - a free international competition for children in mathematics.
Centre for Education in Mathematics and Computing (CEMC) - free online math resources from the University of Waterloo.
ELMACON - a math contest for elementary school students in Vancouver, British Columbia.
Math Performance Centre - promotes and supports math through the arts.
Kangaroo sans Frontieres - organize an annual Kangaroo contest with the aim of promoting mathematics among young people around the world.
Canadian Math Kangaroo Contest - the annual Kangaroo contest held in Canada for students of grade 1-12.
USA Kangaroo Math - contest for students grade 2-12 in the USA.
Art of Problem Solving - comprehensive site for problem solvers, aimed at high school students.
Virtual Mathematics Marathon - an ongoing math contest with news problems added every week for grades 3-12.
Asian Pacific Mathematics Olympiad - annual math competition for high school students.
NS Math Circles - dedicated to enriching students in all areas of mathematics.
IXL - math learning resources from JK up to Grade 12. Limited daily free access + monthly subscriptions.
Brilliant.org - interactive online courses for math, sciences, and programming, accessible by monthly subscription
Kiddle.co - visual search engine and encyclopedia for kids
Studocu.com - A student-to-student knowledge exchange platform

Games, Quizzes, etc

Knowre.com - gamified, personalized online core supplement for Grades 1-12
Mathigon.org - the 'math textbook of the future' with interactive math manipulatives and activities
Prodigygame.com offers a free, adorable Pokemon-style math learning adventure game up to Grade 8.
Maryville University Business and Math Games has a wide range of games and links to game sites.
TVO resources for kids has a wealth of video content including as section called Homework Zone. Examples of the math content for grade 3-6 are mathmaster, scisquad machine mystery and prime radical spentominoes
BBC Math Games - other games also available.
Grade 3/4 practice - from Nelson Education.
National Library of Virtual Manipulatives - some math activities.
MathAmaze - free multiplayer online game from Mitacs.
PBS Kids Games
KiwiCo - monthly subscription for delivery of crates of hands-on STEAM learning projects
IMAGINARY - short texts on aspects of modern mathematics written by researchers visiting the Mathematisches Forschungsinstitut Oberwolfach in Germany and edited for ease of understanding.

Educational YouTube Channels we enjoy

CanadaMath - channel with tutorials for Canadian and American math competitions
Mathologer - accessible explanations of hard and beautiful maths with great animations and graphics
VSauce/D!NG - entertaining videos on math, science, and philosophy presented by the quirky Michael Stevens
Veritasium - interesting videos about science, math, and more
Numberphile - math education channel sponsored by the Mathematical Sciences Research Institute (MSRI)
Mark Rober - Former NASA engineer promoting science and the scientific method via entertaining engineering projects
Smarter Every Day - this channel, run by Aerospace engineer Dustin Sandlin, revolves around scientific exploration and discovery
It's Okay to be Smart - Dr. Joe Hanson presents various scientific and mathematical topics in a fun way. Other PBS Digital Network channels are just as excellent.

Equity, Diversity, and Inclusion (EDI)

IndigenousMathematicians.org - an inspiring international community of Indigenous mathematicians
Organizations that Empower Minorities - organizations and institutions that support the advancement and training of minorities in the mathematical sciences
Accessible Education Materials - resources and technologies to make teaching math more accessible
Association for Women in Mathematics - a community that promotes equitable opportunity and treatment of women and others of marginalized genders and gender identities

Books we like

"Sequences, Combinations, Limits" by S.I. Gelfand, M.L. Gerver, A.A. Kirillov, N.N. Konstantinov, and A.G. Kushnirenko
ISBN 0-486-42566-5
"Functions and Graphs" by I.M. Gelfand, E.G. Glagoleva and E.E. Shnol
ISBN 0-486-42564-9
"Algebra" by I.M. Gelfand and A. Shen
ISBN 978-0-81763-677-7
"The Method of Coordinates" by I.M. Gelfand, E.G. Glagoleva and A.A. Kirillov
ISBN 978-0-81763-533-6
"Trigonometry" by I.M. Gelfand and M. Saul
ISBN 978-0-8176-3914-3