CREATE TABLE "narrow_gauge_locomotives" (
  "class" text,
  "number_s" text,
  "drg_number_s" text,
  "quantity" real,
  "year_s_of_manufacture" text,
  "type" text
);

Question: What is the average quantity that has 1104 as the number(s)?
SQL: SELECT AVG("quantity") FROM "narrow_gauge_locomotives" WHERE "number_s"='1104';

Question: What class has 99 201 as the DRG Number(s)?
SQL: SELECT "class" FROM "narrow_gauge_locomotives" WHERE "drg_number_s"='99 201';

Question: What type has 5 as the quantity?
SQL: SELECT "type" FROM "narrow_gauge_locomotives" WHERE "quantity"=5;