Math sites

Code.org
Code.org provides the leading curriculum for K-12 computer science (link).

Desmos - Type in elementary or the specific content (adding fractions)
Graph functions, plot data, evaluate equations, explore transformations, and much more – for free (link)!

Figure This!
Math challenges for families (link).

FunBrain
Games, videos and ebooks for pre-K through 8 (link).

Greg Tang Math Games
We all love Tang Math, however, they are adding more free games & activities (link).

Hooda Math
Free online math games site (link).

Illuminations
Quality standards-based resources for teaching and learning mathematics, including interactive tools for students and instructional support for teachers (link).

Illustrative Mathematics
Instructional and assessment tasks, blog posts, curriculum blueprints, videos, downloadable documents, and more (link).

Investigations in Number Data and Space
A collection of K-5 math activities that families can do together in both English and Spanish (link).

LONG + LIVE + MATH At Home
A free blend of textbook and software resources and support to help you facilitate at-home learning for your math class (link).

Math for Love
Math puzzles, games, math-art shows and other ways to learn math while having fun! For parents, teachers and students (link).

Math Learning Center
Resources by grade level (PK-5) (link).

Mathsnacks (Middle School)
Educational animations, games, and interactive tools that help mid-school learners better understand math concepts (link).

ScratchGarden
Music videos about math! (link)

Ten days of Math lessons for grades K-5
10 days of activities that teachers can choose to assign to students for them to complete at home (link).

Virtual Manipulatives
A library of uniquely interactive, web-based virtual manipulatives or concept tutorials for mathematics instruction (K-12 emphasis) (link).

Which One Doesn't Belong?
Thought-provoking puzzles for math teachers and students alike (shapes, numbers, graphs and equations) (link).

XtraMath - Excellent practice to help retain math facts
Effective, efficient, adaptive, and intrinsically rewarding supplemental math activities (link).

YouTube Channels for Math Teachers
Educational video content to help you in the teaching of math for different grade levels (link).