What is standard form of the number three million sixty thousand five hundred twenty

The standard form for three million sixty thousand five hundred twenty is
3,060,520.

Explanation.
There are 520 hundred.
There are 60 thousand.
There are 3 million.

Hundreds contain 3 digits.
Thousands contain from 4 to 6 digits. Because a thousand exceeds 3 digits, a comma is used to separate the hundreds within a thousand.
A million contains 7 to 9 digits. a comma is used to separate the hundreds and thousands.

The picture below shows how the number 3,060,520 is split into the different categories.

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