My coursework task is to investigate why, in a number grid square of 1-100, when a section of two by two squares is extracted and the two opposite squares are multiplied and then subtracted the result is always 10.

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Math Coursework

My coursework task is to investigate why, in a number grid square of 1-100, when a section of two by two squares is extracted and the two opposite squares are multiplied and then subtracted the result is always 10.

I will also be testing and studying whether it is true for three by three, four by four, five by five e.t.c number squares. I shall also be studying what will happen if I change the size of the grid square upon which I am extracting the numbers from.

E.g.

                     2x2 square

                                           3x3 square        

2 by 2 Analyses

                                                     (2x11) - (1x12) = 10

                                                   

                                                   

                (35x44) - (34x45) = 10

                                                     

                                  (3x12) - (2x13) = 10

                (99x90) - (89x100) = 10

        

As we can see the results clearly show that no matter what selection of 2x2 square we use the result will always  be 10.

We can show how and why the result is always 10 by using Algebra, (representing numbers by using letters).

        

           =

This is how we can express numbers using letters. As with numbers we can also put letters into a formula. This is how it would look:        

(P+10)(P+1)- P (P+11) = 10

Testing the Formula

Now we can put the formula to the test by using it with numbers:

(23x32)- (22x33) =10

           =

As we can see the formula has proven to work well and the result is once again 10 as the formula suggests.

Now that I have proven the formula with 2x2 squares extracted from a

1-100 grid square, will the formula still apply to a 3x3 square and will the result be 10?

        (3x21)- (1x23) = 40

        (36x24)- (34x56) = 40

        (67x89)- (69x87) = 40

        (80x98)-(78x100)=40

As we can see the result is clearly 40, no matter what section of the number square we use. We can once again show why the result is always 40 by using algebra as formulas.

        

(P+20) (P+2) – P (P+22)

Now we can put the formula to the test by using it with numbers:

(57x75)- (55x77) =40

           =        

As we can see the formula has proven to work well and the result is once again 40 as the formula suggests.

Now that we have proven the formula for the 2x2 and 3x3 squares we can now move on to the 4x4 squares and see what the result will be. Will it be 10 or 40 or something else?

                   (4x31)- (1x34) = 90

                      (64x91)- (61x94) = 90

        (70x97)- (67x100) = 90

          (37x64)- (34x67) = 90

As we can see the result is clearly 90, no matter what section of the number square we use. We can once again show why the result is always 90 by using algebra as formulas.

        

(P+30) (P+3) – P (P+33)

Now we can put the formula to the test by using it with numbers:

(5x32)- (2x35) =90

                                =        

As we can see the formula has proven to work well and the result is once again 90 as the formula suggests.

We shall now try it with a 5x5 square and see what the outcome is…

                                                          (5x41) - (1x45) = 160

Join now!

                                                   

                                                   

                      (50x86) - (46x90) = 160

                                                     

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