Place value is the value each digit has in its position: in order from higher to lower value, there is thousands, hundreds, tens, and ones.
When you divide by 10, you are moving (only once) every digit from its present place value to the right.
For example 6430 : 10= 643, you have moved every digit to the right, making the zero disappear (or better yet, separated by a hidden and in this case useless comma).
