to add
To add 20 and 80; To add 20 to 80; To add together 20 and 80
To add up the even numbers; To tot up the even numbers; To add the even numbers (together)
To learn how to do addition; To learn how to add up
To make a mistake in the addition
plus
Salary plus commission
Three and three are six; 3 plus 3 is/makes 6
communist
Red China; Communist China