This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
abacus hat beads addition add sum computation I'm now adding in the th position from the left the rightmost position the ones position. This is done in steps add subtract . In this step subtract . This completes the computation. For final result see photo ampquotMe adding to itself on abacus in righttoleft order Step ampquot.