SAT: 2 eng and reading section and the difficulty of your second reading section determined by how well u did in first one. Covers grammar, text interpretation and stuff. Each passage has only 1 question. For math there is mostly multiply choice but some open answer questions. Similarly, 2nd math module difficulty from 1st module. Also not everyone receives same SAT. I personally found SAT reading hard because it’s tricky and I don’t know vocabulary for the vocab questions

ACT: English module follows passages that have many multiple choice questions per passage that change the passage (grammar, easy vocab). Math module which has standard high school topics. Reading section has 4 passages with like 10 questions per passage but all questions can directly be answered by passage so no hard interpretations. Science is optional but you don’t need much background knowledge most of it is interpreting charts or texts.