G4 invited guests from League for Soroban Education of Japan Okinawa Branch to learn how to use Japanese abacus, 

 

 

and to do mental calculation with quick-displayed numbers.

 

 

One of the students who used abacus for the first time left a comment; 

 

 

“It was hard to follow the rules on how to push the beads with fingers, but everyone learned it very smoothly and enjoyed calculating!”