This is a set of 25 numbered (and repeated un-numbered) task cards with 25 different 3rd grade math problems, aligned to Common Core 3.OA.D.8 and similar state standards. These problems switch between: unknown start, unknown change, unknown result, mixed and two-step, for the four operations. An answer key with both final answer and using an X for the unknown, as well as a blank answer sheet, are also provided. These task cards are not labeled as Common Core - we have separate listings for…