Maths Coursework - T-Total

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Jamie Bustin         Math’s Coursework        March/April 2007

Objective

In my coursework I have to work out a series of formulae to determine the total of the numbers contained in a t-shape encased in a number square after a variety of different transformations.

The t-total is the sum of the numbers in the t-shape, highlighted in yellow in the below grid sample. The t-number is the number at the base of the t-shape. Highlighted in red in the right example/ or is fourteen in the example grid below.

Working out the T-Total

In this section I am going to develop a formula to determine the t-total from the t-number that will work for any locations on any size grids. In order to work out the formula, I am going to mentally calculate the t-totals and see if I can locate a pattern in the results, which I shall place in a table I created below. I will then create a formula-t-shape to display and prove the formula I discover.

I am beginning with a 9x9 grid

   

I calculated the T-Total for a number of different T-Numbers and entered my results in the table below.

I noticed that each time the T-Number increased by 1 there was an increase of 5 in the T-Total. I thought therefore that the formula would have 5n in it. It was then just a case of working out the rest of the formula. E.g.

So in my 9 x 9 grid, when n = 20, 5 x n is 100. I calculated that I had to subtract 63 from this total to get the T-Total.

(20x5=100)-63=37

I then repeated this with n being 21 and noticed that again I had to subtract 63 to get the T-Total.

(21x5=105)-63=42

I then had to prove my formula so I created the ‘formula-t-shape’  

(N is the t-number)         

Join now!

=

Using a t-number of 38 I’m going to work it out mentally and then using the formula to see if they are the same.  

Formula=        (5x38=190)-63=127

Adding=                (28+29+21+20+19) = 127

That is my proven formula.

        

I then tried the same technique on a 10x10 grid

 

And an 8x8 grid

And then came up with ...

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