Help students develop addition skills by learning how to quickly add long strings of one-digit numbers. This can be a useful and fun skill for students of any age or skill level. Included is a lesson overview, printable worksheet with answer key and colorful slides to show in the classroom.Complements of 10 are two numbers that add up to 10, such as1 and 92 and 83 and 74 and 6and so on...