Used for logical consistency, especially in stories, explanations, or arguments. Often appears in phrases like つじつまが合う (to be consistent) or つじつまを合わせる (to make things consistent).
His story doesn't add up.
証言のつじつまを合わせる必要がある。
We need to make the testimonies consistent.
His story doesn't add up.
After telling the lie, I had a hard time making everything add up.
The two people's testimonies don't match up.