The correct statement is "the first months of Franklin Roosevelt's presidency when Congress passed numerous important laws."
Once he was elected president in 1932, FDR went to work immediately to help the American economy recover from the New Deal. This New Deal were different pieces of legislation he proposed that would help America to recover from the Great Depression. In this short span, FDR was able to get fifteen different laws passed. After this presidency, the phrase "100 Days" has been used as a measuring stick for a president's success shortly after their inauguration.
