What standard form means

Standard form differs depending on the type of thing you're referring to. In imaginary numbers, standard form is where the real number comes before the imaginary number (i. e. 6 + i of - 3 - i)

However, in linear equations, standard form is when something is written as y = mx + b (y = 6x + 5 or y = 9x + 7)

There are many different standard forms mathematically.

Standard form is a way of writing down very large or very small numbers easily. 103 = 1000, so 4 * 103 = 4000. So 4000 can be written as 4 * 10³. This idea can be used to write even larger numbers down easily in standard form.