On: Making a digital clock in Google Sheets

[walty]

To fix it, you can change cell U1 from

  =iferror(regexextract(text(HOUR(A1),"##"),"^\d"),"0")

to

  =iferror(regexextract(text(HOUR(A1),"00"),"^\d"),"0")

The ## text format uses only as many digits as needed, while the 00 format pads to 0 digits.