IF I GIVE 10 APPLES OUT YOU GIVE 3 TO SOME 1 THEN HE GIVE 1 TO SOME 1 ELSE THERES STILL BEEN 10 APPLES PUT OUT
Please stop embarrassing yourself. Experienced traders are telling you how an exchange measures trade volume. Listen to them.
All they do is measure buys and sells. Every time there is a trade volume is added. Even if the same coins are being bought and sold. Trade volume is simply swaps.