The first grade teachers at school absolutely love introducing subtraction and addition number sentences to their kids using the book Ten Flashing Fireflies by Philemon Sturges. I discovered this book in a lesson recorded in a Math Solutions book entitled Minilessons for Math Practice K-2. There is also a similar lesson (I think…not positive) in another Math Solutions book entitled Teaching Arithmetic. In the lesson students model the action of gathering fireflies into a jar using snap cubes. In the book there is a jar printable to use or the lesson suggests using a sheet of blue construction paper to represent the night sky. Not only is this lesson good for introducing the action of subtraction and addition, but it is also good for discussing one more and one less. Because this is such a beloved book that builds a great foundation for addition and subtraction, I worked on building this free SMART Board lesson to accompany the book this weekend, and so here is an example of this lesson. Just click to download the SMART Board lesson for free.
To save time on making a number line with math fonts, which is a bit tedious, I decided to search online. I stumbled over this WONDERFUL website full of fabulous math freebies. There are math power points, smart board lessons, printables, flashcards and the like for primary students. Just to name a few: one to one correspondence smart board lessons, number lines 0-100 printable, and counting by grouping objects power point. All of the many downloads on this site are especially good for the common core standards, which focus so heavily on number sense and counting for primary students.