The USA didn't get involved in the war until Japan bombed the American fleet in Pearl Harbor, in Hawaii in 1941. After the United States got bombed they declared war one day after the bombing. Within a few days after the US declaring war on Japan, Germany and Italy declare war in the United States. While these wars were going on in 1945 Adolf Hitler commits suicide on April 30, with Germany surrendering seven days later. Two days after that Germany surrenders too the Soviets also.
The war continued between the United States and Japan for about three months after Germany surrenders. The Untied States drops an atomic bomb on Hiroshima on August 6, 1945. This shocks Japan. Japan doesn't surrender though. Three days later the United States drops another atomic bomb on a different town called Nagasaki. The Japanese having agreed in principle to unconditional surrender on August 14, 1945, now formally surrender on September 2, 1945.
The war continued between the United States and Japan for about three months after Germany surrenders. The Untied States drops an atomic bomb on Hiroshima on August 6, 1945. This shocks Japan. Japan doesn't surrender though. Three days later the United States drops another atomic bomb on a different town called Nagasaki. The Japanese having agreed in principle to unconditional surrender on August 14, 1945, now formally surrender on September 2, 1945.