What does abacus mental arithmetic mean {one by one, one times five to four, one times nine to one}? More specifically, I have no foundation at all. Please, everyone.

"One, five, four, one, one, one, one, one" means to dial a bead.

"From five to four" means that when five add up and one becomes six, the five beads below are knocked down by four.

"Going from one to nine" means that when a number changes into ten numbers, nine beads are removed from one number, and ten numbers are added with one bead.

Extended data:

Ten-fold formula of abacus mental arithmetic division

One time (divided by 1): one time, two times, three times, four times, five times, six times, seven times, eight times and nine times.

Two returns (divided by two): every two into one, every four into two, every six into three, every eight into four, 2 1 plus five.

Three returns (divided by three): three into one, six into two, nine into three, three into one, three into two.

Four returns (divided by four): every four enters one, every eight enters two, four two adds five, four twelve is more than two, and four thirty-seven is more than two.

Five cycles (divided by five): every five cycles into one, 5 1 cycle is two, 52 cycles is four, 53 cycles is six, and 54 cycles is eight.

Six returns (divided by six): one every six, two every twelve, six three plus five, six one plus four, six two three left two, six four left four, six five eight left two.

Seven returns (divided by seven): every seven returns to one, every fourteen to two, every seven to three, every seven to six, every seven to four, every seven to five, every seven to five and every seven to four.

Eight returns (divided by eight): every eight enters one, 84 adds five, 8 1 adds two, 82 adds four, 83 adds six, 856 is greater than two, 867 is greater than four, and 878 is greater than six.

Nine returns (divided by nine): every nine returns to one, nine returns to one, ninety-two returns to two, ninety-three returns to three, ninety-four returns to four, ninety-five returns to five, ninety-six returns to six and ninety-seven returns to six.

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