T-Total Coursework

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Kamran Adnan (10 S2)        Maths Coursework        T-Total

Part 1

Here we have a grid with nine numbers in a row starting from 1 and ending with 81. There you can see the shape, which is marked in red colour. This shape is called a T-Shape. The T-Shape is always a shape of five numbers.

The number at the bottom is 20. This number is called the T-Number. The sum of all the five numbers is called the T-Total. In this case the T-Number would be:

1 + 2 + 3 + 11 + 20 = 37

To find out a relationship between the T-Number and the T-Total we need more results in the same grid.

In this grid we have six more T-Shapes. Now we need to find out their T-Totals.

1 + 2 + 3 + 11 + 20 =        37        

2 + 3 + 4 + 12 + 21 =         42

3 + 4 + 5 + 13 + 22 =        47

4 + 5 + 6 + 14 + 23 =        52

Looking at the results we can see that if the T-Number goes one up the T-Total goes five up. This is because by raising the T-Number by one, each number of the T-Shape will go one up. Because there are five numbers in a T-Shape the T-Total goes 5*1 = 5 steps up.

The formula for finding out the T-Total by using the T-Number is 5*N – 63. The following is an explanation how I found this formula out.

I already knew the T-Total for the T-Number 20. As we can see in the results is that every time the T-Number goes up one, the T-Total goes up five. So I had to multiply 20 by 5 because the T-Total goes five up if the T-Number goes one up. The answer was 100. Then I found out the difference between 100 and 37, because 37 was the actual T-Total. The difference was 63. Therefore I knew that the formula had to be 5*N-63.

The number 63 I also found out by doing the following calculations (T-Number is 77):

(77 – 68) + (77 – 60) + (77 – 59) + (77 – 58)

9 + 17 + 18 + 19

= 63

This means that you have to add up all the differences between the T-Number and the other numbers of the T-Shape.

There is also another place where this 63 came from. If you multiply 9 by 7, the answer would be 63. I got the 9 from the grid size which was nine numbers in a row. At the end of my coursework, after I found out the formula for the grids of other sizes, I realized that always the numbers in the formula was dividable by 7. If we had for example a grid with 10 numbers in a row, the number in the formula would be 7*10 = 70. The seven works with all sizes of grids.

I will demonstrate now that the formula 5*N-63 is correct:

The T-Total of 23 is 52. To check rightness of my formula I will use it:

5*23 - 63 = 115 - 63 = 52 


To be completely sure I am going to use the formula to find out some other results.

In the grid there are some other examples of T-Shapes, which are not in the same lines. This will prove that there is no difference in the formula even if the T-Number is not on the same line.

The T-Number 65

5*65-63 = 262

Check:                46 + 47 + 48 + 56 + 65 = 262

The T-Number 80

5*80-63 = 337

Check: 61 + 62 + 63 + 71 + 80 = 337

The T-Number 53

5*53-63 = 202

Join now!

Check: 34 + 35 + 36 + 44 + 53 = 202

Now we can be 100% sure that the formula for finding out the T-Total in a grid with 9 numbers in a row is 5*T-Number-63.

I also found another formula of finding out the T-Total. This formula would be:

T = N + (N - 9) + (N - 17) + (N - 18) + (N - 19)

This formula can be used, too because the distance between the numbers in a

T-Shape never changes. For example:

So in ...

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