a. It all adds up
b. [It/that] adds up/doesn't add up

1. This year both Venus Williams and Serena Williams, not to mention Maria Sharapove, Jennifer
　　Capriatti, Kimika Date and Ai Sugiyama will be competing at Wimbledon. Clearly it all adds up to
　　a exciting tournament ahead for the tennis fans.

2. Truman thought about the camara canister that fell from the sky; the radio announcer talking
　　about him; the appearance of his father; and how everybody seemed to follow him. It was all
　　starting to add up - he was convinced there was a conspiracy.

a. 合計で見るとーーしか考えられない
b. 腑に落ちる・落ちない

3. It [=your explanation/what you said] just doesn't add up.

それはどうもわからない話だ
[腑(ふ)に落ちない].

4. The Pyramids, the Valley of the Kings, the towering columns of the ancient temple at Karnak,
　　the lush valley of the Upper Nile … it all adds up to the holiday of a lifetime.