T-Total.I was set the task of investigating the relationship between the T-number and T-total on different grid sizes and different positions on the grid.

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Mathematics GCSE Coursework

T-Total

Say you had a 9 by 9-number grid with a T-shape drawn on it. The total of the numbers inside the T is 1 + 2 + 3 + 11 + 20 =37.

This is called the T-total.

The number at the bottom of the T-shape (20 in this case) is called the T-number.

I was set the task of investigating the relationship between the T-number and T-total on different grid sizes and different positions on the grid.

What I will aim to find out is a formula that will link the T-number and T-total in some way or another. First I will find out the difference between the different T-numbers and T-totals in the grid (sticking to only a 9x9 for now)

So it is easier and quicker to write I will use the following letters to represent certain numbers: -

-    X = grid length

  • N = T-number
  • T = T-total

The difference between the first T-number (20) and T-total (37) is 17.

This is the next T (not T-total but T-shape) along.

The T-number here is 21.

The T-total = 2 + 3 + 4 + 12 + 21 = 42

42 – 21 = 21

 

N = 22

T = 47

Difference = 25

N = 23

T = 52

Difference = 29

So, the difference so far starting from the first T look as followed:

  1. 17  
  2. 21  
  3. 25
  4. 29

The differences are going up by 4 each time i.e. the 2nd difference is constant therefore it is a quadratic equation. (Ax² + Bx + C)

It appears that using these results will not work in a quadratics table or equation because the differences have to be in the same category EG/ just T-total.

The T-total appears as followed:

  1. 37
  2. 42
  3. 47
  4. 52

The T-total is going up by 5 each time.

This shows that the 1st difference is constant i.e. linear. (Ax + B)

T-no. = 24

T-total = 57 (+5 from previous T-total)

If you multiply the 1st T-no. by 2 (20x2) then -3 from the product you get 37.

(20 x 2) -3 = 37 (the t-total for this T-no.)

If you multiply the 2nd T-no. by 2 (21x2) you get 42, which is the correct T-total for 21. (Nothing added or subtracted)

3rd T-no. x 2 (22x2) = 44, which is 3 less than the correct T-total 47. So you’ll add 3.

4th T-no. (call these T1, T2, T3…) x2 (23x2) = 46, which is 6 less than the correct T-total 52.

It appears that what you have to add to the doubled T-no. is going up by 3 each time.

Strangely, although it may be a mere coincidence 3 is the square root of 9, the grid length. It will be interesting to see if this works with other sized grids.

 

There are 5 numbers within the T itself. This is bound to be significant somewhere.

Difference between T-no. and the other numbers within the T: -

20 – 11 = 9

20 – 3 = 17

20 – 2 = 18

20 – 1 = 19

Imagine that all the numbers within the T were the same as the T-no. i.e. 20.

 -19   -18  -17

If I multiplied 20 by 5 that would give me 100, the total of all the 20s in the T. To get to the T-total I would have to subtract all the differences (-19, -18, -17, -9) which would get me to the same number that I would get from adding all the numbers in the T in the first place i.e. the T-total.

I.e. What I’m aiming to do is to use the differences I just worked out (between the T-no. and the other numbers in the T) with the 100 (20 x5) to get to the T-total.

Join now!

EG/ 20 + 11 + 3 + 2 + 1 = 37

EG/ 100 – Total of differences (63) = 37. (Correct T-total)

Now, I will try the newly found way with other various T’s from within the grid.

21 – 12 = 9

21 – 4 = 17

21 – 3 = 18

21 – 2 = 19

Same differences as before, because each number goes up the same amount as any other number in the square wherever you move it so they are all going to stay the

same to each other.

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