Pokemon Resistance Chart In Pokemon Tcg,the New Cards Have Resistance And Weakness + Number Beside The Type Symbol, What That Mean?

In pokemon tcg,the new cards have resistance and weakness + number beside the type symbol, what that mean? - pokemon resistance chart

in Pokemon TCG, new maps have the strengths and weaknesses of + the number next to the symbol rate, what does this mean?
I'm an old school player and I especially the oldest cards in the game, though sometimes very rare, so to play with him, even against the new cards, but I need to know about this new strength and weakness of the + or - Numbers, behind my back had no idea what that means, continue to apply the double attack of weakness, then add a number on that amount? dommmages or just this number? same resistance that I need to know, I thank you in advance