The 17 digits abacus, also called a counting frame, is a calculating tool where beads are moved up and down and by feeling and looking at the beads, complex calculations are made. Calculations made by the abacus / is a integration of mind and body. Abacus / is a magical tool to make brain smarter. Features - - Material: durable hard plastic (frame and beads), and wood (rods). - Size (L*W*H): about 10.5*2.3*0.7 inch. - and Plastic Abacus Arithmetic Kid’s Calculating Tool 17 Digits. - style abacus, plastic frame, 17 digits. - One bead above and four beads below. - Give concrete visible display of numbers by beads. - A very useful tool in general mathematics education. - Widely used by kids, accounting students, merchants, traders, etc. Package list: 3 * Portable Plastic Abacus Arithmetic Kid's Calculating Tool 17 Digits