It means you can enter Singapore twice between 31st July and 4th September inclusive. You can enter on the last day (4th September) and be given a period of stay (usually 30 days but can vary) provided you fulfill the other immigration requirements (passport valid 6 months, onward or return ticket, sufficient funds).

What is meant by valid upto?

adj. 1 having some foundation; based on truth. 2 legally acceptable.

What does valid number mean?

Valid number means a number for a specific telephone terminal in an assigned area code and working central office that is equipped to ring and connect a calling party to such terminal number. Sample 1. Sample 2.

Valid is used in slang to refer to an individual or something that is of high standard. It is cool and exciting, according to Urban Dictionary.