This is an investigation to find a relationship between the T-totals and the T-number. The diagram shows a 9x9 grid, with each individual cell having one number in it starting on the

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Lianne Haley

COURSEWORK INVESTIGATION

T-Totals

The Problem, the Plan and possible extensions

This is an investigation to find a relationship between the T-totals and the T-number.

The diagram shows a 9x9 grid, with each individual cell having one number in it starting on the top row 1-9.

The diagram shown has an upright T-shape, the total of the numbers inside the T-shape is 1+2+3+11+20 = 37, and this is called the T-total.  The number at the bottom of the T-shape is called the T-number.  The T-number, for the example T-shape given, is 20.

I need to be systematic in my approach so initially I will be investigating the relationship between the T-totals and T-numbers when the T-shape translates on the 9x9 grid, starting with the 1st row then the 2nd row etc.  This will keep it simple for me to spot any patterns.

Later I will be investigating T-shapes on different sized grids, again translating the T-shape to different positions on the grids to find a relationship between the T-totals and the T-numbers.

I can also use grids of different sizes again and try other transformations and combinations of transformations and investigate relationships between the T-totals, the T-numbers, the grid size and the transformations.

Hypothesis

Looking at the 9x9 grid, and the example T-shape given, I would expect that when the T-number increases by 1 the T-total will increase by 5 as there are five number squares within the T-shape and translating the shape to the next possible arrangement would increase all the numbers in the T-shape by 5.


Results

Below is a 9x9 grid with each T-shape in the first row overlapping another T-shape to represent each T-shape pattern on row 1.

I have tabulated my results to see if there is a pattern emerging.

Row 1 (1-9)

From my findings I notice that the T-Totals form a sequence:

37, 42, 47, 52, 57, 62…

The T-totals increase by 5 every time, although the numbers have no relation to the 5 times table.


Row 2 (10-18)

Again as in the first row I have tabulated my results for the second row to see if the pattern is the same.

Join now!

Straightaway after the first two rows we see a pattern is developing which is that when the T-Number increases by 1 the T-total increases by +5.

I will now look into developing a formula which can be used to determine the T-Totals for randomly placed T-Shapes on the same 9x9 grid.


Generalisation

If I was to find the T-Total for any T-shape on a 9x9 grid I would need a formula.  Let n = the T-Number and t = the T-Total.

i.e.

In this case:

n = 77

t = 322 ...

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