The formation of thousand numbers

The video tutorial introduces the concept of thousands, explaining how it is a new family of numbers greater than hundreds. It demonstrates the transition from the greatest three-digit number, 999, to 1000 by adding one. The tutorial further explains the place value system, showing how digits are carried over from units to tens, hundreds, and finally to thousands. It concludes with counting in thousands and identifying the greatest four-digit number, 9999.

Explain how to carry over when adding numbers in different places.

What is the greatest 4-digit number?