1, the abacus from right to left in order is a, ten, hundred, thousand, ten thousand, as shown below:

2, the abacus above two beads, the following five beads, as shown in the following figure:

3, full of five on a bead, full of ten into a bead, as shown in the following figure:

4, for example, the twenty-five plus seventeen, the first twenty-five in the abacus to beat out the abacus, and then add seven to become thirty-two, and then add ten to become forty-two, as shown below:

4, for example, twenty-five plus seventeen, first twenty-five, and then On the addition of seven into thirty-two, and then add ten into forty-two, as shown below: