# How to Solve the [1-28] Puzzle in 5 Easy Steps

If you love logic puzzles, you might have come across the [1-28] puzzle. It’s a simple but challenging game that involves filling a 7×4 grid with the numbers from 1 to 28, following some rules. The rules are:

- You can only use each number once.
- The numbers in each row must add up to 40.
- The numbers in each column must be in ascending order.
- The numbers in the shaded cells must be even.
- The numbers in the unshaded cells must be odd.

It might seem impossible at first, but with some logic and strategy, you can solve it in no time. Here are five easy steps to help you crack the [1-28] puzzle:

## Step 1: Start with the corners

The corners are the easiest places to start, because they have only one possible number that fits. For example, the top left corner must be 1, because it’s the smallest odd number and it’s unshaded. The bottom right corner must be 28, because it’s the largest even number and it’s shaded. Fill in these two numbers and move on to the next step.

## Step 2: Use subtraction to find the missing numbers in each row

Since each row adds up to 40, you can use subtraction to find the missing numbers. For example, if you have a row with 1, ?, ?, 16, you can subtract 1 and 16 from 40 and get 23. That means the two missing numbers must add up to 23. Since they are both odd and unshaded, they must be 9 and 14. Fill in these numbers and repeat this process for each row.

## Step 3: Use the column order to narrow down the options

Since each column must be in ascending order, you can use this rule to eliminate some options. For example, if you have a column with ?, 8, ?, ?, you know that the first number must be smaller than 8 and even. That means it can only be 2, 4, or 6. Similarly, the third number must be larger than 8 and even, so it can only be 10, 12, or 14. The fourth number must be larger than the third number and even, so it can only be 12 or 14. Use this logic to narrow down the options for each column.

## Step 4: Use the shaded cells to find the even numbers

Since the shaded cells must be even, you can use this rule to find some of the even numbers. For example, if you have a shaded cell with two possible options, such as 10 or 12, you can check if either of them is already used in another shaded cell in the same row or column. If so, you can eliminate that option and fill in the other one. For example, if you have a shaded cell with 10 or 12 as options, and another shaded cell in the same row with 12 as an option, you can eliminate 12 and fill in 10. Repeat this process for each shaded cell.

## Step 5: Use trial and error to fill in the remaining cells

If you have followed the previous steps correctly, you should have only a few cells left to fill in. You can use trial and error to find the correct numbers for these cells. For example, if you have an unshaded cell with two possible options, such as 3 or 5, you can try one of them and see if it works with the rest of the grid. If not, you can erase it and try the other one. Be careful not to erase any numbers that you have already confirmed. Repeat this process until you fill in all the cells and complete the puzzle.

Congratulations! You have solved the [1-28] puzzle! Here is what the final solution looks like:

| | | | | | | |

|—|—|—|—|—|—|—|

| **1** | **11** | **13** | **15** | **17** | **19** | **21** |

| **

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