Addition is the mathematical way of putting things together.

## Arithmetic

In arithmetic, addition is finding the total of two or more numbers. The sign for addition is "+". The name for the sign "+" is "plus". Another name for the total is the sum.

### Counting examples

For example, there are objects in two groups. The objects are small circles: "o". One group has five of these objects. The other group has 3 of these objects. To find the total number of objects in both groups, the objects can be counted. Another way to find the number of objects in both groups is to add the numbers in each group.

Another method is to add the numbers of objects in group A and group B, since they are already counted. In symbols:

5 + 3

There are rules for adding numbers that people learn. There are also rules for adding numbers that are built into machines (binary adder). The rule says that:

5 + 3 = 8

In another counting example, Sally and Bill have 2 children. Sally and Bill get 3 more children. Sally and Bill have added three children to their two children and now have five children.

### A measurement example

Tom wants to know the distance between his house and Sally's house. Bob's house is 300 meters east of Tom's house. Sally's house is 120 meters east of Bob's house:

Tom's house<------------300 meters-------------->Bob's house<-----120 meters----->Sally's house

The distance from Tom's house to Sally's house can be found by adding the distances already measured. The distance from Tom's house to Bob's house added to the distance from Bob's house to Sally's house is the same as the distance from Tom's house to Sally's house. That is, three hundred (300) meters plus 120 meters.

300 + 120 = 420