How to Abacus Exercise - Mixed Friends

Three groups of Friends come to help you learn abacus. Here is the Mixed Fiends team containing 6, 7, 8, and 9. Follow the formulas and practice the exercises, you'll be a pro of abacus in no time. Don't forget Big Friends and Little Friends. How to Abacus Exercise has a series of exercises for you to sharpen your abacus and mental math skills. Be sure to check them all.