Answer
1,000,000,000,000
Work Step by Step
In standard form, each 3 digits from the left is a period.
$\ \ \ \ \ \ \ \ billions\ \ \ \ \ thousands$
$\ \ \ \ \underbrace{1},\overbrace{000},\underbrace{000},\overbrace{000},\underbrace{000}$
$trillions\ \ \ \ millions\ \ \ \ \ ones$
