her children are at school. right? 'her children' is singular but how can use 'are'
her children are at school. right? 'her children' is singular but how can use 'are'?
If 'her children' can to be plural

Question

her children are at school.  right? 'her children' is singular but how can use 'are'
her children are at school.  right? 'her children' is singular but how can use 'are'?
If 'her children' can to be plural

Answer

"children" is plural,  "her" is singular. and "are" is referring to "children" not to "her" so you refer to a plural using "are",  hope that helps