What is the definition of value in math?

I will answer this with an example:

John was payed $25,000 last year. This year he was payed $31,000. The difference between these two is clearly $6,000: this is also known as the absolute value. Therefore Absolute value is the new value minus the old value. Clear cut right? But what is the relative value?

Relative value is the percentage of change. To solve for this, take relative value (6,000) and divide it by the original value (25,000). 6,000/25,000 = 0.24 or 24%. This is the relative value. The percentage of change between the old value and the new value. Hope this helps.