How to play Sum Grid
Sum Grid is a number puzzle in which you cross out digits. The grid is full of digits, and every row, every column and every coloured area has a target sum. You remove digits until the ones that are left add up to the right total everywhere. Each puzzle has exactly one solution and can be worked out without guessing.
Sum Grid rules
- The grid starts completely filled with digits.
- Each row has a sum on the left, each column has a sum at the top, and each coloured area has a small sum in its corner.
- Cross out digits until the digits that remain in every row, column and coloured area add up to exactly that sum.
- Crossed-out digits don't count; the rest all do.
- Each puzzle has exactly one solution.
How to solve a Sum Grid
A digit bigger than the sum must go
If a row has to add up to 6 and contains a 7, that 7 can never be part of the answer. Cross it out straight away. Check columns and coloured areas the same way; on a new puzzle this often removes several digits at once.
When the sum equals the total, everything stays
Add up all the digits in a row. If that total is already the same as the row's sum, nothing in that row may be crossed out, so circle every digit. This is less common than the first trick, but when it happens it settles a whole line.
Use rows and columns together
Every digit sits in a row, a column and an area at the same time. When you know a digit has to stay in its row, circle it, and that tells you something about its column too. If the column now only needs a small amount more, the other digits in that column may have to go. Switching between rows, columns and areas is how the harder grids get solved.
Playing Sum Grid in Vellara
Sum Grid is one of the puzzles in Vellara that are switched off by default. You will find it at the bottom of the main menu under More puzzles, and you can put it in the main menu yourself in Settings, under Puzzles in the menu.
Tap a digit to cross it out. Tap again to circle it when you are sure it stays, and tap once more to clear it. A sum turns grey as soon as its row, column or area is right, so you can see at a glance what still needs work. Undo takes back a step, Check shows how you are doing and Clear starts again. You can make the grid smaller or larger, or fit it to your screen.
There are five levels. The easiest is a 3×3 grid to get you started; the hardest is a 12×12 grid, the largest. In between come more coloured areas and more to add up, and on the higher levels you sometimes need to think ahead. Every puzzle has exactly one solution.
A clock runs while you play, but there is no time pressure. Take as long as you like.
Sum Grid FAQ
What is the circle for?
A circle marks a digit you are sure has to stay. It doesn't change the sums, but it helps you keep track of what you have already decided.
Where can I find Sum Grid in Vellara?
It is off by default. Look at the bottom of the main menu under More puzzles, or switch it on in Settings under Puzzles in the menu.
How do I know a row is finished?
Its sum turns grey when the remaining digits add up correctly. The same happens for columns and coloured areas.
Do I need to be good at maths?
Not really. You only add small numbers, and the puzzle is more about logic than arithmetic. Every puzzle can be solved without guessing.
Is Sum Grid free?
Yes. Vellara is free to download and play, and you don't need an account.
Download Vellara
Vellara is free for iOS and Android, needs no account, works offline and never sends you notifications.