CREATE TABLE table_52688 ("Driver" TEXT, "Constructor" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

How many laps for denny hulme with under 4 on the grid?
SELECT SUM("Laps") FROM table_52688 WHERE "Driver" = 'denny hulme' AND "Grid" < '4'
SELECT SUM("Laps") FROM "table_52688" WHERE "Driver" = 'denny hulme' AND "Grid" < '4'