What is the formula of abacus calculation?

1, one up one, two up two, three up three, four up four, five up five, six up six, seven up seven, eight up eight, nine up nine. One drops five to four (4+ 1), two drops five to three (3+2, 4+2), three drops five to two (2+3, 3+3, 4+3) and four drops five to one (1+4, 2+4, 3+4).

2. One to nine into one (9+ 1), two to eight into one (8,9+2), three to seven into one (7,8,9, +3), four to six into one (6,7,8,9+4) and five to five into one (5,6,9+4).

3. Six on one to five into one (5, 6, 7, 8+6), seven on two to five into one (5, 6, 7+7), eight on three to five into one (5, 6+8) and nine on four to five into one (5+9).

Addition exercise:

Three times nine (put one two three four five six seven eight nine on the abacus, then add a few times and add three times. The first pass was 2469 13578, the second pass was 493827 156 and the third pass was 9876543 12. )

Nine times nine (hit one two three four five six seven eight nine on the abacus, and then add one two three four five six seven eight nine every time, nine times. After the first pass: 2469 13578, after the second pass: 3703700367, after the third pass: 493827 156, after the fourth pass: 6 17283945, after the fifth pass: 7407400733.