What is the difference between "Wasze dziecko i Twoje dziecko"? also isn't wasze plural?
If you were asking whether "wasze" is for plural objects… Here it's written "wasze" and not "wasza" or "wasz", because "dziecko" is a neuter noun. Remember that possesive pronouns must agree not just with the owner and number of objects, but also its gender.
It's exactly as you say - 'twoje' is singular, 'wasze' is plural.
In English 'your' is ambiguous and can be used for both singular and plural, but in Polish you have to be specific.
You uses "Twoje" if you say this to one person and "Wasze" if to group of people ;)
Wasze is plural but dziecko singular? I got translation "Your children" incorrect. Correct is Your child. So why is it not Twoje dziecko?
The plurality of „wasze” in this case refers to the multiple owners, not multiple objects. Here, many people (probably two) has one child.
"your children" would be either twoje dzieci or wasze dzieci, depending on whether you are speaking to one person or more than one person, respectively.
If you want to say "your child," then it would be either twoje dziecko or wasze dziecko, again depending on whether you are speaking to one person or more than one person, respectively.