1994 Saxon Math 2: An Incremental Development -- Home Study Teacher's Edition (TE)(Spiral) by Nancy Larson, Roseann Paolino, & Dee Dee Wescoatt *** 9781565770157 *** 736
Not as good as the original Saxon levels (5/4+). No mention of number bonds and how addition and subtraction are related. If a kid memorized the addition tables then they should be able to do all subtraction problems too- but ONLY if they understand the relationship between the functions.
Singapore has the advantage there- it stresses this from the beginning. And the workbooks and textbooks are incredibly engaging with colorful pictures and activities. Also, the workbook pages for early Saxon are repetitious and boring which makes engaging with the material more difficult for young children.
Singapore is great until level 4 or 5 and then I recommend switching to Saxon 5/4.