1. The abacus is one, ten, hundred, thousand and ten thousand from right to left, as shown in the following figure:

2. There are two beads on the abacus and five beads below, as shown in the following figure:

3. Put a bead on the fifth one and a bead on the tenth one, as shown in the following figure:

4. For example, if you add 17 to 25, you can first type 25 on the abacus, then add 7 on the abacus to become 32, and then add 10 to become 42, as shown in the following figure: