These answers really helped me w my assignment! I’d like to contribute. For part 2 calculations, I did:

double numProductF = ((double)num1) * num2 * num3 * num4; double numAvgF = (num1+num2+num3+num4)/4.0;

The mistake I was doing was not including the (double) for the first number, as Mureinik and others said. Just this double was enough for me to finally get it. The explanations also make a lot of sense. Thank you!