CREATE TABLE table_40985 ("Class" FLOAT, "Date" TEXT, "Builder" TEXT, "No. built" FLOAT, "1919 nos." TEXT, "LMS Class" TEXT, "LMS nos." TEXT)

In 1879-81 with number built 4, what is the LMS nos?
SELECT "LMS nos." FROM table_40985 WHERE "Date" = '1879-81' AND "No. built" = '4'
SELECT "LMS nos." FROM "table_40985" WHERE "Date" = '1879-81' AND "No. built" = '4'