Cross-figure facts for kids

A cross-figure is a fun puzzle that's a lot like a crossword, but instead of words, you fill in numbers! Each empty box in the puzzle grid gets a single digit. These puzzles are also sometimes called cross number puzzles or figure logic puzzles. The numbers you need to find are given to you through different types of clues.

What Are Cross-Figures?

Cross-figures look just like crosswords, with a grid of black and white squares. But instead of letters, you put numbers into the white squares. Each number you enter must fit the clue given for its row or column. It's a great way to use your math skills and logic!

How Do Clues Work?

Cross-figure clues can be tricky and fun. Here are some ways they might give you hints:

• Direct Clues: Sometimes, a clue will tell you the number directly. For example, "27 times 79" or "The seventh prime number". These clues often test your general knowledge or basic math.
• Linked Clues: Many clues depend on other answers you've already found. For instance, a clue might say "25 across times 3" or "9 down minus 3 across". You'll need to solve one part of the puzzle to unlock another!
• Hint Clues: Some clues give you a hint but not the exact answer. A clue like "A prime number" means the answer could be 2, 3, 5, 7, and so on. You'll need to use other numbers in the grid to figure out which prime number fits.
• Rearranged Digits: A clue might say "5 across with its digits rearranged". This means you take the numbers from 5 across and put them in a different order to get the new answer.
• See Another Clue: Some entries might not have their own clue. Instead, they tell you to "See 13 down". Then, 13 down might say "7 down plus 5". This links different parts of the puzzle together.
• Grouped Clues: Sometimes, several answers are linked by one clue. For example, "1 across, 12 across, and 17 across together contain all the digits except 0". This means the numbers in those three answers will use every digit from 1 to 9 exactly once.
• Algebra Clues: Some puzzles use letters to stand for unknown numbers, like "A - 2B". You have to figure out what A and B are to solve the clue.
• Story Clues: A puzzle might be based on a story, like a family trip. Clues could be "Time taken to travel from Ayville to Beetown". These make the puzzle feel like a real-life problem.

Important Rules

There are a couple of unwritten rules in cross-figures:

• Numbers usually cannot start with a zero. For example, 0123 is usually not allowed; it would just be 123. (Some puzzles might say if they allow zeros at the start).
• No two answers in the puzzle should be exactly the same number.

Solving a Cross-Figure

At first, a cross-figure might seem impossible because you can't fill in any numbers without knowing others. But the trick is to think differently! Instead of trying to find whole answers right away, you can slowly narrow down the possibilities for each single box or part of an answer.

For example, imagine 12 across and 7 down both have three digits. If the clue for 12 across is "7 down times 2", you can figure out a few things:

• The last digit of 12 across must be an even number (because it's "times 2").
• The first digit of 7 down must be 1, 2, 3, or 4 (because if it were 5 or higher, "7 down times 2" would be a four-digit number, but 12 across only has three digits).
• The first digit of 12 across must be between 2 and 9.

By using these kinds of logical steps, you can slowly fill in the puzzle. Even the person who creates the puzzle often tries to solve it themselves. This helps them make sure there's only one correct answer!

Why Aren't They More Popular?

Cross-figures are not as well-known as crosswords. This is mainly because you need some basic math skills to solve them. Because of this, not many books of cross-figures have been published.

However, some magazines do feature them! Dell Magazines publishes a magazine called Math Puzzles and Logic Problems six times a year. It often includes about a dozen of these puzzles, which they call "Figure Logics". There was also a magazine called Figure it Out that focused on number puzzles, but it didn't last very long.

Because they are less common, cross-figures don't have as many strict rules or "conventions" as crosswords do. One interesting convention is using a semicolon (;) to join numbers. For example, if you see 1234;5678, it means the number 12345678. Some puzzles choose not to use this or other non-math ways to create numbers, preferring to stick to pure math logic.