How can addition be described in terms of counting?

Addition can indeed be described as counting-up the total. When you add two or more numbers together, you are fundamentally combining quantities to find out how much there is in total. This process is akin to starting from zero and counting up each value you are adding.

For example, if you have 3 apples and you add 2 more apples, you can visualize this as starting at 3 and then counting up two more: 4 (one apple) and 5 (the second apple), which leads you to the total of 5 apples. This highlights how addition is directly related to the action of counting up to reach a total.

The other options do not capture the essence of what addition represents. Subtracting involves taking away from a total, counting in equal groups refers to multiplication or division, and determining differences pertains to subtraction again. Therefore, focusing on counting-up exemplifies the process of addition perfectly.