Finding the number of squares in any given grid can be a daunting task because the squares can be of many sizes. Fortunately, you can use mathematical formulas to find the answer as long as the grid is the same size on every side. To find the total number of squares, use the formula n (2n + 1) (n + 1) / 6, where "n" is the number of units on each side of the grid. You can also find the number of differentsize squares by thinking through all the possibilities.

Find the number of 1by1 squares. For a 6by6 grid, you would multiply 6 by 6 to get 36.

Find the number of 2by2 squares. You can try to count them by hand, but its is easier to use the mathematical formula (n  1) x (n  1), where "n" equals the length of each side. You calculate (6  1) x (6  1), or 5 times 5, to get a result of 25.

Find the number of 3by3 squares. Multiply (n  2) x (n  2), or 4 times 4, to get a result of 16.

Find the number of 4by4 squares. Multiply (n  3) x (n  3), or 3 times 3, to get a result of 9.

Find the number of 5by5 squares. Multiply (n  4) x (n  4), or 2 times 2, to get a result of 4.

Find the number of 6by6 squares. Multiply (n  5) x (n  5), or 1 times 1, to get a result of 1.

Add up your results to get the total number of squares in a 6by6 grid. Add 36, 25, 16, 9, 4 and1 to get a total of 91 squares.
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