Number Stairs

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Number coursework 1

In this piece of coursework I am going to investigate the relationship between the stair total and the position of the stair shape on the grid. I am also going to further investigate about the stair total and grid size.

I will use (T) for my stair total, and (N) for my stair number.

                                                                         Stair number (N), which is 1.

By calculating the sum of all figures inside the stairs gives you the stair total.The symbol for the stair total is (T). With the stair number 1 we get a stair total of 1+2+3+11+12+21=50. The stair total is calculated accordingly to the stair number.

                                                                       Stair number (N), which is 2.

Thus our stair total for this stair grid in the 10x10 grid is, 2 + 3 +4 +12 +13 +22 = 56. Therefore T = 56.

                                                                                                  Stair number (N) = 3

If, N = 3, then T = 62. Here we can see that the stair total is calculated by, 3 + 4 +5 +13 +14 +23 = 62.Therefore, the addition of all the figures inside the stair.

                                                                                  Stair number (N)

If N = 4, then T = 4 + 5 +6 +14 +15 +24 = 68.

The following table shows the stair total (T) depending on the relevant stair number:

50    56    62    68    74

+6                        +6                           +6                       +6

It is clear that the difference between the numbers is 6. This means that the formula, to solve the total, must include a multiple of 6. This will lead to the fact that the nth term has to have6nin the formula, the extra is calculated by working out what is left over this will be+44.Therefore, the formula has to be T =6n + 44. By substituting the stair number to the nth term we get the stair total. The way how the formula work is the following:

Which means that (6 x STAIR NUMBER) + 44 = STAIR TOTAL.


Now that I have worked out the formula for the 10x10 grid I am going to use the formula in random staircases with random stair numbers. And those are:

    Stair number = 17

    Stair total = (6x17) + 44 = 146, or alternatively, 17+18+19+27+28+37= 146.

Stair total = 57+58+59+67+68+77= 386

By formula, stair total= (6x57) + 44= 386

Stair total = 71+72+73+81+82+91= 470

By formula, stair total = (6x71) +44= 470

Here is an alternative way to find the stair total of the 10x10 grid by using further algebraic method.


As we can see here n=stair number, and the 3x3 stair case from the 10x10 grid can be substituted in to the formula staircase for the 10x10 grid.

Total for algebraic staircase = n+n+1+n+2+n+10+n+11+n+20= 6n + 44.

By substitution: 1+1+1+1+2+1+10+1+11+1+20= (6x1) + 44 = 50= Stair total

Here is another example:

        


Total for algebraic staircase = n+n+1+n+2+n+10+n+11+n+20= 6n + 44.

By substitution: 57+57+1+57+2+57+10+57+11+57+20= (6x57) + 44 = 386, whereas stair number=57

(PART 2)

Now I am going to undertake further investigations between the stair total for other size grids. For example, 9x9, 8x8, 6x6, etc.

Here are a 9x9 grids showing the stair total and stair number:


                                                                      (For 9x9 grid) stair number=1

By calculating the sum of all figures inside the stairs gives you the stair total. With the stair number 1 we get a stair total of 1+2+3+10+11+19= 46. The stair total is calculated accordingly to the stair number for any grid size. This is a 9x9 grid size.


                                                                         Here we can see that the stair number =2

For the 9x9 grid our stair total will be 2+3+4+11+12+20=52, if the stair number=2.

                                                        Stair number=3                                                                          For the 9x9 grid our stair total will be 3+4+5+12+13+21=58, if the stair number=2.

The following table shows the stair total (T) depending on the relevant stair number for the 9x9 grid. Which are from 1 to 5.

46    52    58   64    70

                 +6                                 +6                                   +6                         +6

It is clear that the difference between the numbers is 6. This means that the formula, to solve the total, must include a multiple of 6. This will lead to the fact that the nth term has to have6nin the formula, the extra is calculated by working out what is left over this will be+40.Therefore, the formula has to be T =6n + 40. By substituting the stair number to the nth term we get the stair total. Here we can see that is clearly evident that the nth term for the 9x9 grid has decreased by 4 as compared to the 10x10 grid.  The way how the formula work is the following:

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Which means that (6 x STAIR NUMBER) + 40 = STAIR TOTAL.


Now that I have worked out the formula for the 9x9 grid I am going to use the formula in random staircases with random stair numbers. And those are:

    Stair number = 61

    Stair total = (6x61) + 40 = 406, or alternatively,                 61+62+63+70+71+79= 406

Stair number=7

Stair total= (6x7) + 40= 82

With out the nth term the stair total= 7+8+9+16+17+25=82

Stair number=55

With out the nth term stair total= ...

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