The first one is correct.
Since 5 x 400 = 2000, 5 x 400 is also 20 hundreds.
It equals 20 hundreds
Which equals 2000.
Good Luck on your test!
(I HATE GO MATH! IT'S THE MOST STUPID THING ON EARTH! I AM A MIDDLE SCHOOL HONORS CLASS STUDENT. WE STILL USE STUPID GO MATH.)You can ask your parents if you still have questions.