Party A sues Party B in court for $10,000 due to breach of contract. Party B denies the claim and holds that Party A owes them $5,000 due to breach of the same contract.
Can Party B counter sue Party A during the same court case or is Party B required to file a separate lawsuit against Party A for the counter suit?
Assuming not, would it matter if Party B agrees that it owes Party A $10,000 but because of the breach by Party A (of a different provision of the contract) it holds that the amount should be reduced by $5,000?