How to Add and Subtract One-Digit Numbers

Let's say I wanted to add . When you add one to any number, you get the next number. So here is the counting: , , , , , and our answer is next, . So,

Another way to do this would be to count on my fingers. I have fingers on each hand. I hold out one hand, and put finger up on the other. Then, I count all the fingers, giving me: .