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Since the childhood days we have been memorizing the tables of numbers saying :

two ones are two (2 x 1 = 2)

two twos are four (2 x 2 = 4)

two threes are six (2 x 3 = 6)....

However recently I came across a rule stating that if the mathematical operation of two or more fixed numbers(constants) yields a fixed numeral, then the singular form of verb should be used to denote the operation connecting the operands and the result. This makes the sentence look like :

Two twos is four.

Is it really so??

Edwin Ashworth
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Maroof Kazmi
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  • Two comments: the rule you are stating is called the closure properties of addition and multiplication also please note, 2 X 3 = 6 not 2 X 2 = 6 – user 85795 Jun 05 '14 at 10:00
  • @skullpatrol - 2 x 2 = 6 for sufficiently large values of 2. :P – oerkelens Jun 05 '14 at 10:04
  • There is, I believe, a subtle difference between 'two and two make/s four' and 'two and two is four', which is not addressed in the claimed duplicate. – Edwin Ashworth Jun 05 '14 at 10:52

1 Answers1

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The sentence two twos are four is correct, but although it is a common English phrase, it is not mathematical - in actual mathematics, the equations is not pronounced that way.

In mathematics, the equal sign is pronounced as equals or simply is.

It denotes that everything on the left equals everything on the right, hence the singular.

However, in mathematics, no-one will ever pronounce 2 x 2 = 4 as two twos are four.

Two times two equals four
Two times two is four

Are both acceptable, and indeed, the singular is used to indicate that the parts on the left and the right of the equal sign are seen as complete, whole, singular expressions. (So even 7 times 5 plus 3 divided by 12 minus 2 is seen as a singular expression.)

The simplified two twos are four is in itself correct, as it strays from the strict mathematical domain. It aims at visualizing for children that 2 x 2 = 4 can be seen as two occurrences of a concept "2". In that case, since we are actually counting them, the plural is correct, in exactly the same way as we say

Two horses have 8 legs. (not has!)

oerkelens
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  • So what is the answer to the original question ---> Two and two (is /are) not five....? – Maroof Kazmi Jun 05 '14 at 08:37
  • @MaroofKazmi - the answer to Is this so? is not answerable because it is unclear what this refers to. As I wrote in the last paragraph: "two twos are four is in itself correct". – oerkelens Jun 05 '14 at 08:39
  • @MaroofKazmi - ah - with "original question you mean your title. I missed that as you title does not appear in your question. It is a good isea top include your question in your actual question text. Well, as I wrote that "two twos are four" is correct in the last paragraph of my answer, I don't see what is unclear about which form to use in your title-sentence :) – oerkelens Jun 05 '14 at 08:43
  • I upvoted but did take a little while to find _ ... two twos are four is in itself correct, as ..._, it would be more obvious if it were at or near the top of the answer, but at least it is in there. – Frank Jun 05 '14 at 08:55
  • As the question seemed to be about confusion stemming from the mathematical approach, I focused on that in my answer - but for clarity I have added an executive summary at the beginning of my answer :) – oerkelens Jun 05 '14 at 09:11
  • "two twos is four is correct" no it is not, it is grammatically wrong. The rule about treating it as a singular expression does not apply because you have broken it by describing two expressions. Otherwise this would be a great answer. – JamesRyan Jun 05 '14 at 09:42
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    @JamesRyan: thank you for pointing that out! In my effort to make things more clear so people would not have to read the whole answer I messed it up. Of course, that should be two twos are four is correct! – oerkelens Jun 05 '14 at 09:44
  • What does 'in mathematics' mean? Most 'mathematics' probably 'occurs' in schools, and a decent teacher would give different ways of reading out '2 x 2 = 4'. Tables are still produced with the a x b = c format, and doubtless read out the 'other way'. // 'It denotes that everything on the left equals everything on the right, hence the singular.' But 'bacon and eggs are two of my favourite foods', 'bacon and eggs is my favourite breakfast'. The 'and' operator doesn't determine agreement. 'Two and two make/s four', as in the previous thread. – Edwin Ashworth Jun 05 '14 at 13:36
  • @EdwinAshworth: when I say "in mathematics" I mean "in a language that would be acceptable when used in-context between mathematicians". Primary school level multiplication tables are not that. Since the question was about two twos, where there is no option to say that is singular, I limited my answer to that - and an explanation of the "mathematical" approach that seemed to confuse the OP. – oerkelens Jun 05 '14 at 13:45
  • Thank you. I hope the question is re-opened, though the relative frequencies of 'two and two are four' etc shown in these Ngrams surprise me. – Edwin Ashworth Jun 05 '14 at 13:58