My students love these number puzzles. They are a great way to practice different strategies for adding and subtracting two-digit and three-digit numbers. They help students play with decomposing numbers to build addition and subtraction math strategies for second grade.
Growth mindset visuals. A Poster for students with alternatives and behavior reminders. This one is good, because it is not a "do this" don't do that" poster. It is recommendations for situations that may arise often in class such as being confused about a topic or feeling discouraged because they don't understand
Sites that I can't do without as a math teacher (and what's so special about each one!) Links to virtual manipulatives, discovery-based lessons, free graphing software, question prompts, eBooks, and more.... Tons of resources for math teachers
Math Concentration is a resource that not only provides free math homework help but is a community aimed to building strong parental support and and healthy relationships between learners and educators. They offer free homework help via forum, chat, and virtual whiteboard.