number
1 whole numbers
2 numbers that show position in a sequence
3 fractions
4 exact and inexact numbers
5 doing things with numbers
quantities HOW MUCH/MANY
measurements SIZE, WEIGHT
the study and use of numbers MATHEMATICS
see also ONE, TWO, HUNDRED
1 whole numbers
- a word or symbol that indicates a quantity: number; adjective: numerical
a number between 10 and 20 ◎ The answers were given in numerical order.
- letters that represent numbers (I, II, III, IV, etc): Roman numerals
- a written sign for a number (0 to 9): figure
Write the number in figures as well as words. ◎ a six-figure number (= between 100 000 and 999 999)
- a number that is used to identify sth: number
What's your telephone number?
- used before a number to show its position in a sequence: number (written abbreviation no)
I live at number 16. ◎ I'm staying at the Grand Hotel in room no 134. ◎ What's the answer to question number one? ◎ What number are you on? (= how far have you got in a list of things to do or questions to answer)
- to give a number to sth: number sth; adjective: numbered
Number each page in order from 1 to 20. ◎ I couldn't put the pages in order because they weren't numbered.
- a number that can be divided by two (2, 4, 6, 8, etc) is an even number
- a number that cannot be divided by two (1, 3, 5, 7, etc) is an odd number
- the number 0: zero, nought, nil
Three, two, one, zero and lift off! ◎ I got nought out of ten in the test. ◎ To write a million you put a one followed by six noughts. ◎ The final score was two nil.
- a number which is less than zero is a negative number; (used about a number) below zero: minus
-2 (minus two) is a negative number.
- a number which is greater than zero is a positive number; (used about a number) above zero: plus
a temperature of plus three degrees
Note: in British English nought is normally used when talking about the figure 0 in numbers; zero is more common in scientific and technical uses; nil is used mainly in talking about scores in sport; O (pronounced oh) is often used in giving telephone numbers.
- the names of the numbers: (1) one, (2) two, (3) three, (4) four, (5) five, (6) six, (7) seven, (8) eight, (9) nine, (10) ten, (11) eleven, (12) twelve, (13) thirteen, (14) fourteen, (15) fifteen, (16) sixteen, (17) seventeen, (18) eighteen, (19) nineteen, (20) twenty, (21) twenty-one, (22) twenty-two, etc; (30) thirty, (40) forty, (50) fifty, (60) sixty, (70) seventy, (80) eighty, (90) ninety, (100) a hundred, (1 000) a thousand, (1 000 000) a million, (1 000 000 000) a billion
- a group of twelve: dozen (plural dozen); six or a group of six: half a dozen
a dozen eggs ◎ three dozen bottles of wine
Note: in numbers greater than a hundred, we say and before the last part of the number:
sixty-two ◎ three hundred and two ◎ two thousand three hundred and two ◎ two million six hundred thousand five hundred and ninety-five.
- We usually use a rather than one for numbers between a hundred (100) and a hundred and ninety-nine (199) or for a thousand, a million or a billion:
There are a hundred and fifty people in the school ◎ 'How many have you got left?' 'About a thousand.' If the number needs to be emphasized, we use one:
There are exactly one hundred tickets left. ◎ 'Did you say five hundred?' 'No, one hundred.'; but we usually use one with numbers greater than a thousand, a million or a billion:
one thousand, three hundred and sixty (1 360).
- Numbers between 1 100 and 1 999 can be spoken as hundreds, especially in informal usage:
eleven hundred (1 100). Dates are always written in numbers. When we say dates between 1 001 and 1 999, we usually omit hundred:
in 1066 (ten sixty-six) ◎ 1789 (seventeen eighty-nine).
2 numbers that show position in a sequence
- a number that shows the position of sth in a sequence: ordinal (number)
- the names of the ordinals: first (1st), second (2nd), third (3rd), fourth (4th), etc; twenty-first, twenty-second, twenty-third, twenty-fourth, etc; hundredth; thousandth; millionth; billionth
- introducing the first point on a list: first, firstly
- introducing the second, third, fourth, etc point on a list: second (or secondly), third (or thirdly), fourth, etc
I'll tell you why I'm leaving - firstly, I've got a new job; and secondly, I 'm going to get married.
3 fractions
- a number that is not a whole number (for example, ※µ※※): fraction
- a fraction expressed in tenths (for example, 0.75): decimal
- the dot used in a decimal: decimal point| FRACTION | DECIMAL | | ※½: a half (plural halves) | 0.5: (nought) point five | | ※¼: a quarter | 0.25: (nought) point two five | | ※¾: three quarters | 0.75: (nought) point seven five | | ※¹※※: a third | 0.33: (nought) point three three | | ※²※※: two thirds | 0.66: (nought) point six six | | 1※½: one and a half | 1.5: one point five | | 1※¾: one and three quarters | 1.75: one point seven five |
- to divide sth in half: halve sth
- to divide sth into quarters: quarter sth
4 exact and inexact numbers
- a particular quantity of sth: number (followed by a plural verb)
There was a large number of people waiting for the gates to open. ◎ People came in large numbers. ◎ A small number of cars were parked in the middle of the road. ◎ A number of people were there.
- to say how many people or things there are, you can say that they number a certain amount
They numbered about 30 (= there were about 30 people in total).
- to be more in number than sb/sth else: outnumber sb/sth
Women medical students now outnumber the men in many places.
- correct or accurate: exact (adverb exactly)
We need to know the exact number of people you are expecting. ◎ Can you be a bit more exact please?
- almost correct but not quite: rough (adverb roughly)
I don't need to know exactly, but can you give me a rough estimate? ◎ There is roughly five pounds left.
- in 10s, 100s or 1000s; not being very accurate: in round figures/numbers
He gave the answer in round figures.
- a number greater than nine: double figures
I started off by earning seven pounds an hour but now I'm into double figures.
※ more on being exact EXACT/APPROXIMATE
- a small number of people or things: a few, one or two, (informal) a couple
Only a few (people) came to the party. ◎ I only saw one or two pictures I liked. ◎ A couple of people recognized me.
- to emphasize that a quantity is big, you can say dozens (of ※¦), hundreds (of ※¦), thousands (of ※¦), millions (of ※¦)
Hundreds of people went to the concert. ◎ They spend millions of pounds on computer games.
- to calculate the approximate number of sth: estimate sth; the number you get if you estimate sth: estimate
Can you estimate the length of the room? ◎ It's probably about ten metres long, but that's just an estimate.
- to decrease a number to the nearest whole number: round sth down; to increase a number to the nearest whole number: round sth up
If it comes out at a decimal, round it up to the nearest whole number.
5 doing things with numbers
- to find the answer to sth by adding numbers, taking numbers away, etc: work sth out, calculate sth
I'm trying to work out who owes who what. ◎ I've calculated the cost of going on holiday this year.
- something calculated by using numbers in this way: sum, calculation
to do a sum in your head ◎ to get your sums right ◎ a difficult calculation
- the four types of mathematical calculation: addition (verb: add; symbol: +), subtraction (verbs: subtract, take away; symbol: -), multiplication (verb: multiply; symbol: Ã), division (verb: divide: symbol: ÷)
Note: these calculations can be said as follows:
- 2 + 3 two plus three or two and three
- 9 - 6 nine minus six or nine take away six
- 4 Ã 2 four multiplied by two or four times two
- 8 ÷ 2 eight divided by two
- The answer to a sum is shown by writing the symbol = (called an equals sign) or by saying equals or is
Two and/plus two is/equals four.
- a small electronic machine used for calculating numbers: calculator
- to multiply sth by two: double sth; a number or amount that is two times as big as another one is twice ※¦, double ※¦
Think of a number and then double it. ◎ I work twice the hours he does.
- to multiply sth by three: treble sth; a number or amount that is three times as big as another one is three times ※¦, treble ※¦
- a number that contains another number an exact number of times: multiple
90 is a multiple of 10.
- the number you get when you multiply another number by itself: square; to multiply a number by itself: square sth
100 is the square of 10. ◎ 10 squared is 100.
- a number that produces another number when multiplied by itself: square root
The square root of 49 is 7.
- the number you get when you add two or more figures together and then divide the total by the number of figures you added: average; adjective: average
The average of two, three and four is three.
- the relation between two amounts, calculated by the number of times one is bigger than the other: ratio
The ratio of men to women in the company is three to one. (written 3:1)
※ more on averages AVERAGE
- to say numbers in their proper order one after the other: count
I learnt to count when I was five.
- to say numbers one after another until you get to a particular number: count up to sth
Can you count up to 100 in Japanese?
- to calculate the total number of sth by starting with one and counting upwards: count sth
The teacher counted the children as they got on the bus.
- the amount that you get when you add two or more numbers together: total
- to find a total: total sth (up), count sth up
Count them up and put the total at the bottom.
- to know/not know how many there are of sth when you are counting: keep*/lose* count (of sth)
I can't keep count when there are people asking me questions all the time. ◎ I'll have to start again, I've lost count.
- to count sth again: re-count sth: noun: re-count
I'm sure there should be more than that - I'd better do a re-count.
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