To work out the sum of two large numbers:

- set the numbers out in columns
- line up the units digits
- start by adding the units digits
- then work across to the left

## Software/Applets used on this page

## Glossary

### union

The union of two sets A and B is the set containing all the elements of A and B.

### work

Equal to F x s, where F is the force in Newtons and s is the distance travelled and is measured in Joules.