• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7
8. 8
8
9. 9
9
10. 10
10
11. 11
11
12. 12
12
13. 13
13
14. 14
14
15. 15
15
16. 16
16
17. 17
17

# Number pyramids

Extracts from this document...

Introduction

Number pyramids

## Plan

I am trying to investigate a formula, so that I can calculate the base for small number pyramids, for example the base numbers of a pyramid 1, 2,3 etc. By the end of this I should be able to use that formula to calculate any amount of numbers used for the base of pyramids.

## Challenge

The challenge is whether you can predict the finishing number for a pyramid, which has 17 numbers along the base and starts with 23. This challenge has to be carried out without guessing or drawing the actual number pyramids.

What is a number pyramid?

8

35

1   2   3

A number pyramid is basically adding the two consecutive numbers at the bottom in order to get the second row of numbers. Then you would add those two numbers to get the top number. So therefore it is essentially adding continuously in order to get the numbers above.

## Method

16            20          24           28

7  9         9  11     11  13      13  15

3  4  5     4  5  6      5  6  7     6  7  8

You will be able to notice that by looking at 3 numbers at the base, the first row has a difference of 1, the middle number goes up by 2 and the top number goes up by 4. So therefore you would multiply the middle base number by 4, in order to get the top number.

 First Number Last Number Top Number 1 3 8 2 4 12 3 5 16 4 6 20 5 7 24

Once I have put the results in a table, I can analyse them carefully and work out a general formula. If you look at the first number column, you will be able to notice that they go up by 1, and the top number column goes up by 4. So therefore, if you add any first number to any last number and then multiply it by 2, you will get the top number. In that case, my formula is as follows: -

(F + L)  x 2 = T

By using this formula I can calculate any first, last and top number.

Test my formula (F + L)

Middle

Formula: (F + L) x 16 = T

Substituting: (1 + 6) x 16 = 112

After I have substituted the numbers into the formula, you will see that the top number of a six-based pyramid is 112; the same number appears after I have calculated the formula above. So this means the prediction I had made earlier on for the 6 based pyramid is correct.

However, now to work out a general rule, I will use the following table to distinguish this.

### Base Numbers

The number you multiply by the first and last number

### Power Form

3

2

2

21

4

4

2 x 2

22

5

8

2 x 2 x 2

23

6

16

2 x 2 x 2 x 2

24

By carefully observing the table above you will notice that in order to get from the base number to the power number, you would have to minus 2 from the base number. So therefore in order to prove this rule, if I had a base number of 17, the outcome power form would be 215.

However, if I were to do this using algebra, I would have the letter ‘B’ as my base number to represent any number and the power form would be 2B-2

So therefore my general formula is: -

Top =  (F + L) 2B-2

Now in order to test my general formula, which is as follows:-

Top = (F + L) 2B-2

I will use the number pyramid below, to prove that my formula functions correctly.

?

5    7

2   3   4

By studying the number pyramid you will have noticed that it has a base of three. Now in order to prove my formula, I will substitute the general formula into the number pyramid.

Formula: Top = (F + L) 2B-2

Substitution: Top = (2 + 4) 23-2

Top = 6 x 21

Top = 12

By viewing the above calculation, you will have noticed that my general formula works, so therefore the answer to the three-based pyramid above is proved correctly as 12.

After proving my general formula, I have now presented the formulas for each base pyramid.

Conclusion

have to take away 2 each time.

Now, that I have calculated the difference of 3, by applying the three base numbers, I will now predict how the formula will look like for the 6 based pyramid. The formula will appear something like the following: -

 6 (2F + 15) x 16 = T 24

However, now in order to prove my formula, I will substitute the formula into the six-based pyramid.

32F +240

16F+96   16F+144

8F+36     8F+60      8F+84

4F+12    4F+24   4F+36  4F+48

2F +3    2F+9   2F+15   2F+21  2F+27

F   F+3   F+6   F+9  F+12  F+15

Formula: (2F + 15) x 16 = T

Substitution:  (F + F + 15) x 16

= 2F x 16 = 32F

= 32F + 240

By observing the above calculation, you will notice that my formula for the six-based number pyramid is correct.

Now, in order to work out a general formula for the differences of 1, 2, 3 and 4, I will use the following table, to input the formulas.

 Differences Formulas 1 (2F + B-1) 2B-2 2 (2F + 2 (B-1) 2B-2 3 (2F + 3 (B-1) 2B-2 4 (2F + 4 (B-1) 2B-2

By studying the table above, you will notice that 2F stays the same and the number you are adding on each time goes up by 1. However though the rest of the formula stays the same.

As I have already distinguished a pattern for this, I will now calculate a general formula, using algebra.  The formula is as follows:

(2F + D (B-1)) 2B-2

Now in order to prove this formula, I will use the following number pyramid, which has a base of three.

8

3 5

1  2  3

Formula: (2F + D (B-1)) 2B-2

Substitution: (2x1 + 1 (3-1) 23-2

= (2 +1 (2) 21

= (2 +1 (2)) 21

= 2 + 2

= 4 x 21 = 8

By looking at the formula above, you will have noticed that my calculations are correct, as the top number of the three based pyramid is equal to 8, which is the same, when I did the substitution.

This student written piece of work is one of many that can be found in our AS and A Level Core & Pure Mathematics section.

## Found what you're looking for?

• Start learning 29% faster today
• 150,000+ documents available
• Just £6.99 a month

Not the one? Search for your essay title...
• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# Related AS and A Level Core & Pure Mathematics essays

1. ## Functions. Mappings transform one set of numbers into another set of numbers. We could ...

= sin x cos y cos x sin y cos(x y) = cos x cosy sin x sin y tan(x y) = (tan x tan y) / (1 tan x tan y) Fixed Point Iteration In fixed point iteration, a single value estimate is found rather than the interval in which the root lies.

2. ## Math Portfolio Type II - Applications of Sinusoidal Functions

= 2.924178114 + 12.119 T(n) = 15.04317811 T(n) = 15 hours and 3 minutes Substitute 144 into n in the function M (n). M(n) = 1.611 sin[0.017(144 - 78.843)] + 12.114 M(n) = 1.611 sin[0.017(65.157)] + 12.114 M(n) = 1.611 sin(1.107669)

1. ## Experimentally calculating the wavelength of an He-Ne laser by means of diffraction gratings

distance from the central bright beam to the first order fringe x (it is assumed that the distances from the central bright beam to either of the first order fringes are the same). Then, one can use the following equation to find ?: tan?

2. ## Maths - Investigate how many people can be carried in each type of vessel.

We will begin by taking one of the equations that was formed earlier (equation (iv)) and will substitute y = 5 into the equation. y - z = 1 5 - z = 1 -z = -4 z = 4 Now we have already solved two variables of the equation,

1. ## Design, make and test a Sundial.

Clock time = (sundial time) - (equation of time) For example: Sundial time = 10:00am Date= January 9th ? Equation of time= -7 Clock time = (sundial time) - (equation of time) = 10:00 - (-7) =10:07am This is the GMT.

2. ## Coding and Modelling - The tools used in my spreadsheets.

- 48w2 24 = 8w + or - 4w 24 = 4w 24 = w 6 The solution holds true with the trend noticed in the final conclusion. In order to expand my investigation further, I will now proceed to investigate the largest square cutout size possible, which will enable

1. ## Investigate the number of winning lines in the game of connect 4.

C=aH+b (original equation) C=aH+b. We put in results from the above table and since the connects has 2 layers we need to put in results twice. 6=a3+b (1) 17=a4+b (2) 11=a (2)-(1) Substitute 'a' which is 11 back into (2)

2. ## Fractals. In order to create a fractal, you will need to be acquainted ...

However, we want to figure out the dimension of the SierpiÅksi Triangle. When trying to explain why the first, second, and third dimensions are recognized as a line, plane, and cube, many fail to know the real reason. People say it is determined by length, width, and height, or the self-similarity in a line and a plane.

• Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to