What is standard notation?

Answer 1

The standard (or scientific) notation for a number is of the form a*10b where

a is a decimal number, greater than or equal to 1 and less than 10, and b is an integer.

so, for example,

123456 = 1.23456 * 105

while 0.01234 = 1.234 * 10-2

Standard notation is particularly useful when dealing with very large or very small numbers.
It is the most used way to show numbers (ex.90)