Part of our hedge has fallen down and we have bought some green industrial fencing to prop it up: this probably sounds horrible but actually looks quite nice and blends in well with the hedge. In the photo above you can see the wood that is propping up the hedge, but you will need to look much harder to see the new, green posts behind. We drove all the way to Bangor to get the new fence – along the North Wales coast – and took the opportunity to stop off at the beach on the way back and let the dog have a paddle.

To put the fence up we have three posts, and these have to be mounted by digging deep holes – about 60cm each. This has taken quite a bit of effort. The next step will be to concrete the posts in place and then attach the fence. The previous fence lasted about ten years. We hope this one will last a lot longer.

The height of each post above the ground is 183cm which is quite high. As 183 is a number that has occurred naturally in my life I thought I’d use it in this blog post. The next part of the post is to use the number 183 to take me on a journey somewhere – it’s a reasonably random process and usually involves a plane. This time I’m using flight Easy Jet EZY183 which flies between Luton and Belfast. Thus, Belfast is my destination for this post.

## Belfast

What do I know about Belfast? I have visited there once before. I was a student in Dublin and took the train up to visit friends in Belfast one weekend. This was in the early 1990s during “the troubles” and I suppose it was quite brave of me to go by myself even if I do say it myself. I don’t remember much about the city – a 10-pin bowling trip and little else.

So I’m pretty much approaching Belfast as if I’d never been before. And the point of writing this is to establish whether I’d like to go again. Usually the two things that appeal to me most about a place are the food and the cycling possibilities.

Belfast appears to be surprisingly good for cycling – I don’t know why it’s surprising, possibly because I’ve never heard it described as a good cycling city. Here are some suggested cycling routes. In fact the whole of Northern Ireland is felt to be excellent. I’d particularly like to cycle along the waterfront.

Now I thought that food in Belfast would be pretty much like food in Chester, Northwest England where I live. I suspect some of it is, but I was thrilled to find a list of foods to try in Belfast. From this article I would be keen to try fish chowder, traybakes, yellowman candy, colcannon and champ.

There are also many things I’d like to visit in Belfast suggested in this article – particularly the Titanic Belfast. Would I like to visit Belfast? The answer is definitely yes. It’s very near to where I live in Northwest England, it’s good for cycling and the food is interesting. There are also a number of places there I’d like to see. If I’m honest, though, I’m not passionate about it and since beginning this blog have found many other places that I’d put higher on this list. I’d give the likelihood of me going a 7 / 10.

## Polite Numbers

183 is a polite number which is lovely to know! It turns out that most numbers are polite – the impolite or “rude” numbers are all the powers of 2 – so fortunately there aren’t many of them and they become fewer and fewer as the size of the numbers increases.

So, what is a polite number?

A polite number is any number that can be written as the sum of two or more consecutive positive whole numbers.

For example, five is a polite number, because we can write it as the sum of two consecutive numbers:

5 = 2 + 3

Nine is a doubly polite number, because we can write it two ways:

9 = 4 + 5

9 = 2 + 3 + 4

And fifteen is an amazingly polite number. We can write fifteen as the sum of consecutive numbers in three ways:

15 = 7 + 8

15 = 4 + 5 + 6

15 = 1 + 2 + 3 + 4 + 5

The number of ways a number can be expressed as the sum of consecutive numbers is known as its politeness.

As with 15, 183 has a politeness of 3 – i.e. it is a very polite number. Here’s how:

183 = 91 + 92

183 = 60 + 61 + 62

183 = 28 + 29 + 30 + 31 + 32 + 33

The first few polite numbers are

3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, and so on

There won’t be another impolite number until 128 and after that 256.

Perhaps these numbers are polite as a subset are prepared to interact with their neighbours whereas the squares of 2 are not.

## Last Thoughts

Belfast isn’t somewhere that I’d considered going before and it has been interesting to read up about it. I love the way a number that occurs naturally in my life takes me on a journey both to a new location and on a journey in number theory – until writing this post I hadn’t known that numbers were capable of being impolite! If I did visit Belfast I think I’d consider a wider trip into Northern Ireland. There are so many possibilities when choosing trips that it’s difficult to know where to begin!