SevenNumbers

Daily Number Sums Puzzle: Cross Out Digits to Hit Totals

Cross Sums is a daily number sums puzzle: a 7×7 grid of digits from 1 to 9, with a total at the end of every row and column. Cross out digits until every line adds up exactly. Each puzzle has just one solution.

How to play Cross Sums

1. Each row and column has a total at its end. The digits you leave in must add up to it.
2. In Cross mode, tap a digit to cross it out and hold it to mark it as kept. Keep mode swaps them: a tap keeps and a hold crosses out.
3. Tap a marked digit again to clear it, or drag across the grid to mark several at once.
4. The puzzle is solved when every row and column hits its total. Fastest solve wins.
5. Stuck? Reveal shows the answer, but a revealed puzzle isn’t ranked.

Tips

• Start with lines whose total is close to the sum of all their digits: only a digit or two can go, so the choice is often forced.
• Lines with a small total work the other way: most digits must go, so look for the few that can stay.
• Any digit bigger than its row’s or column’s total must be crossed out straight away.
• Mark digits you’re sure of as kept as well as crossed out. Kept digits narrow down the crossing lines quickly.
• Check both directions: a choice that suits a row often breaks a column, which tells you which way it goes.

Questions