Exercise 1: Yes, 1.908 x 10^17 is written in scientific notation.
Exercise 2: Yes, 0.325 x 10^-2 is written in scientific notation.
Exercise 3: No, 7.99 x 10^32 is not written in scientific notation. The decimal d must be between 1 and 10, not between 10 and 100.
Exercise 4: No, 4.0701 + 10 is not written in scientific notation. The correct format is d x 10^n.
Exercise 5: No, 18.432 x 5 is not written in scientific notation. The correct format is d x 10^n.
Exercise 6: No, 8x 10^-11 is not written in scientific notation. The correct format is d x 10^n.