These days, you're most likely to find the simple abacus in the hands of preschoolers — with rows of rainbow-colored beads that kids can push around and shake and rattle.

But you can also use them to carry out a range of calculations, from simple addition and subtraction to multiplication and even square roots.

But you can also use them to carry out a range of calculations, from simple addition and subtraction to multiplication and even square roots.

Then they use it for simple counting exercises, before moving on to addition and subtraction. "It gives children a visual understanding of how to perform these operations," Singh says.