Position changes a digit’s value
In base ten, each whole-number place is worth ten times the place immediately to its right. The digit 4 represents forty in 40 and four thousand in 4,000.
Zero keeps a place open
In 4,305, the zero shows that there are no tens. Decomposing the number as 4,000 + 300 + 5 preserves that position even though the zero contributes no amount.
A mistake to avoid
Do not compare two numbers by looking at their largest individual digit. Compare corresponding places from the left after checking how many places each number has.
Worked example
Compare 5,081 and 5,108
Both numbers have 5 thousands. Their hundreds differ: 0 hundreds is less than 1 hundred. Therefore 5,081 < 5,108; the 8 in the first number does not make it larger.