The integer part can only have one 0 because in the mathematical counting system, 0 is a special number, representing "no quantity" or "null value", so the integer part can't have more than one 0. In the decimal counting system, 0 means no number, and 1 to 9 means 1 to 9, so the integer part can only have one 0.

In mathematics, a number can be divided into integer part and decimal part. The integer part refers to the integer part of a number, that is, the digital part to the left of the decimal point.