Mathematical Abacus Line is especially adapted for those who are blind to complete math operations. It is completely different from other abacuses as it has a felt liner under the rods and beads to prevent the beads from sliding if the abacus is accidentally moved. Mathematical Abacus Line also differs in that it has raised vertical notches to help in setting numbers and in using decimals and commas. When it comes to its design, Mathematical Abacus Line has durable plastic frame with thirteen columns of beads.