Cross Number Puzzles (Crossnumbers): A Beginner's Guide

A cross number puzzle is a crossword built from numbers instead of words. The grid looks exactly like a crossword, with black and white squares and "across" and "down" clues, but every answer is a number, and every clue is a little math problem. Also called a crossnumber, cross-figure, or figure logic puzzle, it's the more advanced, adult cousin of the number grid puzzle. This beginner's guide explains how cross number puzzles work, the rules to know, and how to start solving one.

What is a cross number puzzle?

In a cross number puzzle, you fill the white squares with single digits so that each "answer" (a run of white squares, across or down) matches its clue. The difference from a crossword is that the clues are mathematical. Instead of "capital of France," a clue might read:

• "The seventh prime number"
• "9 across minus 3 down"
• "A multiple of 12"
• "The number of days in a leap year"

Because clues often refer to other answers in the grid ("twice 5 across"), the puzzle becomes a web of interlocking math facts. You can't always solve a clue on its own, you solve the grid as a whole, narrowing each square step by step.

The basic rules

Cross number puzzles follow a few standard conventions:

• One digit per white square. Multi-digit answers span several squares, just like crossword words span several letters.
• No leading zeros. A number can't begin with 0, so a three-square answer is a genuine three-digit number (100–999).
• Answers are usually distinct. As an implicit rule, no two answers in the grid are the same number.
• Across and down overlap. Where an across answer crosses a down answer, they share a digit, which is your main source of deductions.

How to solve a cross number puzzle

The approach is different from a crossword, where you might know an answer outright. Here, you usually have to narrow down possibilities cell by cell. A practical method:

1. Start with the most constrained clues. A clue like "a two-digit square number" has only a handful of options (16, 25, 36, 49, 64, 81). One that's fully determined ("the number of hours in a day" = 24) is even better, place it first.
2. Use the crossings. Once you've placed a digit, every answer crossing that square is now constrained. A "3" in the tens place of a down answer immediately limits what that answer can be.
3. Work the references. When a clue points to another answer ("4 across plus 10"), solve the referenced answer first, then compute.
4. Eliminate, don't guess. Like the Wikipedia approach to cross-figures notes, you gradually narrow each square rather than trying to nail a full answer at once. Keep a list of remaining possibilities for tricky squares and let the crossings whittle them down.

A small example

Imagine a clue "1 across: a two-digit multiple of 11." The options are 11, 22, 33, 44, 55, 66, 77, 88, 99. Now suppose the first digit of 1 across is shared with "1 down: the number of legs on a spider" (which is 8). Then 1 across must start with 8, so it's 88. One crossing collapsed nine options to one. That cascade is the joy of crossnumbers.

Cross number puzzle vs number grid puzzle

They're related but distinct:

• A number grid puzzle writes out a complete equation in every row and column, and you fill in missing numbers and operations. The math is explicit and the format is compact, which makes it great for kids and beginners.
• A cross number puzzle is a full crossword grid where each answer is a number defined by a math clue, often referencing other answers. It's larger, more open-ended, and aimed at adult puzzle enthusiasts.

If you enjoy the logic of a number grid but want something closer to a crossword, crossnumbers are the natural step up.

Why crossnumbers are a niche delight

Cross number puzzles have always been rarer than crosswords, partly because they require comfort with arithmetic, and partly because they're harder to construct. That rarity is part of the charm: solving one feels like cracking a code that not many people bother with. They reward exactly the skills a number grid builds, careful arithmetic and patient deduction, just on a bigger canvas.

Build the skills first

The quickest way to get comfortable with number-based deduction is to start with the compact version. Our number grid puzzles train the same instincts, reading equations, using crossings, and narrowing possibilities, in a friendlier format. Learn the method in how to solve number grid puzzles, then take those skills to a full crossnumber.

Frequently asked questions

What is a cross number puzzle?

A cross number puzzle, or crossnumber, is a crossword-shaped grid where every answer is a number and every clue is a math problem, such as "the seventh prime number" or "twice 5 across." You fill the white squares with single digits so each answer matches its clue, using the overlaps between across and down answers to deduce the solution.

What is the difference between a crossnumber and a cross-figure?

They're the same puzzle. "Crossnumber," "cross-figure," and "figure logic" are all names for a crossword-style grid filled with numbers defined by mathematical clues. Different publishers and countries favor different names.

How do you solve a cross number puzzle?

Start with the most constrained clues (ones with few possible answers or a single value), place those digits, then use the crossings to narrow neighboring answers. Solve clues that reference other answers after you've found the referenced number. Work by elimination, narrowing each square rather than guessing whole answers.