A grid of digits and one target number.
Find the four neighboring cells that add up to it.

QuadSum is a number puzzle with a single rule: tap four neighboring cells that form a 2x2 quad and add up to the target. It is a math puzzle and a logic game at once, because you add up what you can see and rule out the squares that cannot work. Every level has at least one solution, so no board is ever a dead end. Play a quick round whenever you have a minute, or come back for the daily puzzle.

You get three mistakes per run, shown as hearts. One heart comes back every 90 seconds of play.

MODES
• Easy - the grid grows from 3x3 up to 6x6, with a timer that counts up instead of running out.
• Hard - grids from 7x7 up to 10x10 against a 60 second countdown, and every correct answer adds 5 seconds back. The grid stops at the biggest size your screen can show with comfortable cells, so narrow phones top out below 10x10.
• Random - picks Easy or Hard for you.
• Daily Challenge - ten levels, the same ones for every player that day.

DAILY CHALLENGE
Every day brings ten levels that are identical for everyone playing that day, so you are working through exactly the same puzzles as everyone else. Clear them to keep your day streak going.

There is also a statistics screen for your results, twelve achievements to unlock, and eleven languages to choose from. There is no account and no sign-in, and the game plays offline apart from the ads.

HOW QUADSUM MAKES MONEY
QuadSum is free to download and it shows ads. Interstitial ads are shown to every player who has not bought the one-time Remove Ads purchase, which takes them away for good. Rewarded ads are the optional extras: watch one only when you want to narrow the search area, reveal one solution, add fifteen seconds in Hard, or get a life back. Ads are served through Google AdMob, which uses an advertising identifier - the Data safety section above has the details. Your progress is stored on your device, while the ads and the purchase go through Google's servers.

One target, four cells. Find the quad.