Final answer:
President Roosevelt invited Truman into meetings multiple times during his presidency, including the Potsdam and Casablanca conferences.
Step-by-step explanation:
President Roosevelt invited Truman into meetings multiple times during his presidency. One notable meeting that Truman attended was the Potsdam conference, which took place from July 17 to August 2, 1945. Truman replaced Roosevelt at this conference, and it was during this time that he expressed his disagreement with some of Roosevelt's concessions to the Soviets. Another significant meeting that Truman attended was the Casablanca conference in January 1943, where Roosevelt and Churchill met to discuss the next steps for peace. Stalin was invited but declined to attend.