Adding 123456789 to itself on abacus in left-to-right order - Step 20

I'm now adding 9 in the 9th position from the left (the rightmost position, the ones position). This is done in 2 steps: add 10, subtract 1. In this step I subtract 1.

 

This completes the computation. The result can be read off as 246913578.

 

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Done