For this activity you will need to have completed all of the Skill Training program on RightLobeMath.com or know all the bead movements for any addition or subtraction. Basically you should be at least a beginning Level 10 abacus student to practice this exercise.
In this exercise we are going to add the number 123,456,789 nine times on the abacus. By adding this same number nine times we will practice all possible bead movements for any addition problem you may encounter. If you do all nine additions correctly you should end up with the number 1,111,111,101. This is great because the sum is an easily recognizable number.
Once we can perform successfully all nine additions, we can also practice all possible subtraction bead movements. Starting from the number 1,111,111,101 we simply subtract the same number 123,456,789 eight times until we arrive at our origin number 123,456,789 on the abacus. Again if we end up with the number we started with you know you executed all your bead movements correctly.
A great practice exercise is start by adding 123,456,789 nine times and then subtracting the same number until you return to the starting point. This is a great exercise not only to practice your bead movements but to build speed as well.