How did you know how many thumbs up and thumbs down your deck received?
Well, this deck went into the top 10, which messes up thumbs count.
But there's
this tool that calculates your arena deck's thumbs.
There's also this formula that calculates the deck's thumbs, assuming your deck didn't go into the top 10:
[(electrum gained)/(base reward)] - (# of wins) = thumbs up
,where base reward varies depending on the league your arena deck is in; bronze is 4, silver is 6, gold is 9 and platinum is 12