Lay the abacus on a flat surface. Position the abacus so the majority of the beads -- the "1" beads -- are closest to you and the "5" beads are away from you. Press all beads to the upper or lower frame boards, respectively -- away from the middle spacer.
Position the abacus so the majority of the beads -- the beads below the horizontal middle spacer -- are closest to you. Add the following three-digit addition problem -- 113 + 521.
Enter the number 113 -- the first number in the equation -- with the abacus. Move the first bead on the bottom of the "hundreds" rod -- the third rod from the right -- up to the middle spacer to indicate "100." Move the first bead on the bottom of the "tens" rod -- the second rod from the right -- up to the middle spacer to indicate "10." Move the first three beads on the bottom of the "units" rod -- or the rod furthest to the right -- up to the middle spacer to indicate "3."
Add 521 by moving the first "5" bead down from the top of the hundreds rod -- the first bead above the middle spacer -- flush the middle spacer to indicate "500." Move the next two beads on the bottom of the tens rod up to the middle spacer to indicate and addition of "20." Move the next bead on the bottom of the units rod up to the middle spacer to indicate an addition of "1."
Count the beads along the middle spacer. Add the single "5" beads and the single "1" bead on the hundreds rod together to equal "600." Add the three "1" beads on the tens rod together to equal "30." Add the four "1" beads on the units rod together to equal "4." You now have the total 634. Repeat the previous steps to add your own three-digit number.