5
5 is a prime number.
1, 1, 2, 3, 5, 8, 13...
A Fibonacci number.
We have five digits on each hand and foot. V, the Roman symbol for five, may originate from the image of a hand with the fingers spread.
Penta- means five. A pentathlon is an athletics contest with five events and a pentagon is a figure with five sides and five angles. A pentasyllabic word has five syllables, like the word pentasyllabic itself.
Pentagram, pentangle and pentacle are all names for a five-pointed star. This mystical symbol was supposed to keep away devils and witches. A pentacle headdress folded from fine linen was sometimes worn as a defence against demons.
A pentagon (left) and a pentagram (right).
A pentagonal bolt is fitted to many fire hydrants in the USA because it is impossible to undo with a normal spanner - most bolts are hexagonal.
A devout follower of Islam worships five times a day facing the holy city of Mecca. The Islamic creed is the 'Five Pillars of the Faith'.
The Five Ks are traditionally worn by The Singhs, who are a brotherhood within the Sikh religion. These are kes, long hair; kangha, a comb; kirpan, a sword; kachh, short trousers; and kara, a steel bracelet.
There are five rings in the Olympic symbol. Basketball is played with teams of five players, and so is five-a-side football.
Five Olympic rings
Many things come in fives: the five senses, the five Chinese elements, and five vowels in the English alphabet.
In Britain, a fiver is a five pound note. In the USA, a nickel is a five cent coin.
'Take five!' means take five minute's rest.
The Five Towns, made famous in the stories of Arnold Bennett (1867-1931), are the towns of Stoke, Tunstall, Burslem, Hanley and Longton in the Staffordshire Potteries. Bennett generated some ill feeling in the townspeople of Fenton, who were left out and claimed as much right to inclusion as the other five.
This familiar pattern is called a quincunx.
Under British law, when you reach the age of five –
- you become 'of compulsory school age',
- you can see a U or PG category film at a cinema,
- you have to pay child's fare on trains,
- you can drink alcohol in private, for example at home.
When you cut through an apple 'the wrong way' you get a five-pointed star. The wild rose has five petals. Apples and roses are part of a large family of plants called ROSACEAE which includes blackberries, raspberries, strawberries, pears, cherries, plums and peaches, all of which have five-petalled flowers. Although cultivated roses have many more petals, if you look beneath any rose, you will still find five sepals around the base of the flower.
Five-fold symmetry is found in apples and other plants in the rose family.
There are only five possible tetrominoes, which are shown in the illustration here. A tetromino is a shape made by joining together four squares.
Pentominoes are shapes made from five squares. How many of these are possible? Only count shapes which cannot be made from each other by flipping them over or rotating them.
Punch is a drink that traditionally has five ingredients - spirits, water, sugar, lemon juice and spice. The name punch comes from the Hindi word for five.
The Five Platonic Solids are the only five convex regular solids it is possible to construct. They are the tetrahedron (four sides), the cube (six sides), the octahedron (eight sides), the dodecahedron (12 sides) and the icosahedron (20 sides).
Five was the lucky number for the superstitious French fashion designer Gabrielle 'Coco' Chanel. In 1921 she chose the fifth day of the fifth month to introduce her new brand of perfume which she called Chanel No. 5. At that time its scent was unlike any others in a market dominated by floral perfumes. It was a huge success and today it is one of the most famous - and most expensive - perfumes available.
