Sum-10 - Number Match Logic Puzzle

Sum-10 (often called Make 10, Ten Pair, or Number Match) is an incredibly engaging and addictive logic puzzle that will test your pattern recognition, mathematical addition, and planning skills. Originated as a classic pencil-and-paper game, it has become a modern puzzle favorite.

The Objective

The ultimate goal of Sum-10 is to clear all numbers from the board by pairing up tiles that meet the matching criteria, leaving an entirely empty grid.

The Tools You Have

Before diving in, here are the elements of the board:

• The Board Grid: A grid organized into 9 columns. Numbers fill the rows from left to right.
• Number Tiles (1-9): Active numbers that can be matched.
• Add Numbers (+): A special action that copies all remaining active numbers on the board in order and appends them at the bottom of the grid, allowing new matching combinations when you are stuck.
• Hint: A tool that analyzes the grid and highlights a valid matching pair.
• Undo: A history tool allowing you to revert recent moves to correct mistakes or explore different solution branches.

The Rules to Follow

You can clear a pair of number tiles if they satisfy two conditions:

1. Value Match: The two numbers must either be identical (e.g. 3 and 3) or add up to exactly 10 (e.g. 3 and 7, 4 and 6).
2. Adjacency: The two numbers must be adjacent:
   • Horizontal: They are next to each other on the same row, OR wrapping from the end of one row to the start of the next row, ignoring any already cleared (empty) tiles in between.
   • Vertical: They are directly above or below each other in the same column, ignoring any already cleared (empty) tiles in between.
   • Diagonal: They are directly adjacent to each other diagonally (i.e. touching corner-to-corner).

If a full row of 9 tiles becomes entirely cleared, that row will automatically collapse and disappear, keeping the board compact and clean.

Simple Strategy

To clear the board efficiently, follow these core strategies:

• Clear Top Rows First: Try to match numbers on the upper rows first. Since empty rows collapse, clearing top rows prevents the board from becoming excessively tall.
• Scan Both Ways: Always look for both identical values and pairs adding to 10. Sometimes matching for a sum of 10 opens up identical matches that were blocked.
• Use Wrap-around Adjacency: The end of a row and the beginning of the next row are adjacent if the cells between them are cleared. This is a very common place to find hidden matches!

Example of Play

Imagine you have three rows:

• Row 1: 1, 2, 3, 4, 5, 6, 7, 8, 9
• Row 2: 1, 1, 1, 2, 1, 3, 1, 4, 1
• If you click 9 at the end of Row 1 and the first 1 of Row 2, they will clear because they add to 10 and are adjacent in horizontal wrap-around!
• If you have a 3 on Row 1 in Column 3 and a 3 on Row 2 in Column 3, clicking both will clear them because they are vertically adjacent in the same column!

Tips for Beginners

• Don’t hesitate to click Add Numbers! When you run out of matches, dealing new numbers is a normal part of the game and actually opens up many new pairings.
• If you make a match that blocks another better match, just use Undo to revert it and try a different combination.
• Pay attention to long vertical cleared columns. They can connect numbers that are far apart, allowing surprising matches!