McGraw Hill Education has an online interactive “Math Toolbox” (as I like to call it). You can select your grade level (PreK-8) and then there are various game boards, story boards and workmats.
School - Transition
36 online games that teach reading skills
Math Games - Fun Online & Free Maths Games for Kids in Elementary 2nd Grade 3rd 4th
This site is amazing! Free math manipulatives for ALL elementary grade levels!
Could do something similar for integrated science and defining the variables for power, velocity etc.
Simple Math Games that demonstrate nearly every 2nd grade math principle. Also has other grade levels.
Ten frame flash cards
PreK math idea.
Butterfly Fractions. Another way how to learn how to add and subtract fractions with unlike denominators.
Math Teaching Resources