Math calculating with two JSONB keys in Postgres?

I have JSONB column with data like:

{"plays": {"win": 90, "draw": 8, "lose": 2}}

How I can calculate sum with win and draw keys?

Something like:

SELECT
    data::json#>>'{plays,draw}' + data::json#>>'{plays,win}' as "total_plays",
FROM
    plays_data;