One More One Less. Great for the beginning of the year to see where everyone stands.
Fill in the missing numbers grids to 100 - 20 different sheets
FREE place value activity
Math - Place Value
math for first grade
Could do something similar for integrated science and defining the variables for power, velocity etc.
10 More/10 Less 1 More/1 Less Freebie
Common Core Math Worksheet--Free 2nd grade math
Add or Subtract? Freebie
7.4.6 Combining and Partitioning Involving Five and Ten: A quick sheet to check a child's understanding of the partitions of 10.
Number Sense to 120 - Classroom Freebies Too