A student read " 3 000 146 as" three thousand one hundred forty-six." how would you explain the students error

The student broke the number up into 2 parts, 3,000 and 146. The correct way of saying the number is three million one hundred forty-six

I'll try answering in a way that makes sense.

the student read the 3 and the 000 together which looked like a thousand, eventhough there should be a comma to divide every three digits. the way it should actually be read is "three million, one hundred forty-six"