Why is 35 x 10 to the fourth power not considered to be in scientific notation?

Answer 1

Scientific notation is a way of representing numbers in the form

a*10b where 1 ≤ |a| < 10 is a decimal number and b is an integer (negative or positive).

In the example given, |a| = 35 which is larger than 10.

Answer 2

Because the mantissa, "35£ is not a rational number in the range [1, 10).