How to find a sum of a number

There's no such thing as the sum of one number. "Sum" is what you have

when you moosh two numbers together into one by adding them.

For example:

If you put 5 pennies into your pocket, and then later, you put 3 more pennies

into there, what's in your pocket now? Don't look, do it in your head.

You said there are 8 pennies now. That's correct. How did you figure it out?

You 'added' 5 and 3 and you got 8. 8 is the 'sum' of 5 and 3.

you have to have two numbers to have a sum. in addition when you add two or more numbers the result you get is a sum.