To solve a 3-by-3 magic square, all of the columns and rows must add up to 15 when entering other numbers in a 3-by-3 square. The other numbers to use range from one to nine.
To solve one of these magic squares, take a piece of paper and write down all of the numbers from one to nine. Take the middle number and place it in the center of the 3-by-3 square. This is also referred to as x in the formula to figure out the other numbers. To use this formula, enter x plus three in the top right corner and x minus three in the lower left corner. Using five as x means the top right number is eight and the lower left number is two.
On the other side of the magic square, enter the formula x plus one in the top left square and x minus one in the bottom right square. In this case, those numbers are six in the upper square and four in the lower square. At this point, there are four spaces open, so fill in the rest of the squares with the numbers that make the rows and columns add up to 15.