②Map+ Reduce map(key val) is run on each item in set emits new-Rey/ new-val pairs reduce(key, vals) is run for each unique key emitted by mapo emits final output8 • map(key, val) is run on each item in set – emits new-key / new-val pairs • reduce(key, vals) is run for each unique key emitted by map() – emits final output Map+Reduce