What does it mean to add two natural numbers? Suppose ayou have two bags, redone bag hasholding five apples and a bluesecond bag hasholding three apples. NowGrabbing grabbinga anthird, empty green bag, move all the apples from the both redfirst and bluesecond bags into the greenthird bag. NowThe the greenthird bag willnow haveholds eight apples. ThenThis illustrates the additioncombination of three apples and five apples is eight. apples; This can also beor statedmore asgenerally: "three plus five is eight" or "three plus five equals eight" or "eight is the sum of three and five". But numbersNumbers are abstract, and the addition of three sugar cubes to a group of five sugar cubes also yields a bigger group of eight sugar cubes. Addition amounts tois a regrouping: two sets of objects which were counted separately are put into a single group and counted
together: the count of the new group is the "sum" of the separate counts of the two original groups.
