Bead strings. Expand the knowledge of children by using these 20 bead strings to learn number quantity and order, counting, adding and subtraction. The beads can also be used to practice addends and minuends. The strings have 20 beads divided into groups of alternate red and white. Combine multiple strings to increase the number count, or apply different values to the colours to use the beads for more than simple counting. Length: 42cm