Hello, everyone. There was an in-class organic chemistry quiz I took recently and my professor posted the answers online. I have been going through the quiz to understand the problems and the answers to them (my professor also explained the answers), but I am still confused about a few of them. I have attached a picture of part of the quiz (It would be too difficult/confusing to explain without it) and was hoping someone could help me understand the 4 blanks that appear before the word "Hz." In other words, can someone please help explain why those answers are what they are? I followed a certain formula, but seem to be unable to obtain the answer on the key. Those are the only four blanks that I am having trouble with. Everything else makes perfect sense. Thank you in advance.

Doing the last line: you know the MHz of the NMR machine: 200 MHz = 200.000.000 Hz. 1.53 ppm (parts per million) of that amount of Hz = (200.000.000/1.000.000) * 1.53 = 306 Hz