Ten front to back worksheets focused on fact families, using the concept of part + part = whole. Two worksheets are "level 1" with sums less than ten. Eight worksheets are "level 2" with sums 18 or less.
Fact families are a wonderful way to relate addition and subtraction and introduce the properties of operations. I found knowledge of fact families especially helpful to students who struggled to memorize their basic facts. The more practice students had with number relationships, the easier it was to add and subtract fluently and remember the basic facts.
The concept of part + part = whole and whole - part = part helped greatly when solving word problems. Students could look for the clues in the problem and determine which piece of information was missing (part or whole). Fact families are a terrific way to introduce this concept.
*Aligned to Common Core Standards for first and second grades*