Math Is Fun
Math Is Fun: Definition of Abacus
You can use an abacus to count, add, subtract, multiply and more. Try this interactive abacus and see if you can make the numbers. Choose "here's more" for some clues. Good luck!
Curated OER
Science Kids: Science Images: Basic Calculator
This photo shows a basic calculator sitting on a desk. The value of Pi is written to five decimal places on the screen.