Hey there! :D
When you have a value, it is usually positive.
For example, if I have 5 chocolate bars, then I have +5 chocolate bars.
When you take away a value, it is usually negative.
For example, I have 3 chocolate bars away, then I would have 3 fewer chocolate bars. (-3)
Integers are negative or positive whole numbers.
12 songs= 12 <== the integer
Delete 5 old songs= -5 <=== the integer
I hope this helps!
~kaikers