## Abacus

# Abacus

Used since ancient times, the abacus is making a comeback in education. This online abacus tool allows students to model all sorts of operations. In the early grades, students can simply use the abacus to represent quantities and numbers, building number sense. As they grow in their abilities, students can use the virtual abacus to represent addition, multiplication, or subtraction problems.

To use the online abacus, simply drag the beads across the rods from left to right or right to left. Students can represent larger numbers by assigning each rod a place value. For example, the dark purple beads represent the one’s place, lavender the 10s place, the blue represents the hundreds place, sky blue represents the thousands place, etc. Students can represent numbers using the different place values and then perform operations. Alternatively, simply have students represent each addend with a different color.

Some activities you might try with the abacus include:

- Represent multiplication problems as repeated addition. For example, 3 x 3 would be shown as 3 groups of 3 beads on the abacus, each group shown with a different color of beads.
- Represent addition problems on the abacus
- Represent large numbers on the abacus, using the place values mentioned above. For example, you might say 5,342, and students would have to show 5 sky blue beads, 3 blue beads, 4 lavender beads, and 2 dark purple beads.

Visit classplayground.com for more resources and printables related to addition and multiplication.