place value sort- an absolute must for a difficult concept!!
Place Value Roll it, Make it, Expand it Math Station -- 4 different levels (this is the highest, other 2 are 2-digit) -- roll dice to make a number then draw it and expand it :)
Teaching With a Mountain View: Teaching Place Value More
Free Place Value Large Numbers Cut and Paste Activity
The Teacher In Me
Could do something similar for integrated science and defining the variables for power, velocity etc.
Classroom Freebies Too: Place Value
Butterfly Fractions. Another way how to learn how to add and subtract fractions with unlike denominators.
Math Teaching Resources