Is it ok nowadays to say numbers instead of digits, while expressing a sum?

( example: 2345 - these four numbers make the sum..) or must I say digits?

• Nowadays or any day, numbers are numbers, digits are digits. One can not substitute one word for the other. However, note that the definition of number includes "digit" as a synonym. – Kris Mar 26 '15 at 10:08
• The words have, and have had for a long time, different meanings. Thus 2 + 3 = 5 uses three numbers and three digits (as each number is single-digit) whereas 7 + 5 = 12 contains three numbers but four digits. – Edwin Ashworth Mar 26 '15 at 10:09
• This is not to say that there is not a confusion over usages. Statements like '... will also explain to the students that when 6-digit figure is written in words how they will write it in numbers' [DA MODEL HIGH SCHOOL PHASE IV.docx] are better avoided. – Edwin Ashworth Mar 26 '15 at 10:55
• @EdwinAshworth Look up "write in numbers" idiomatic expression. – Kris Mar 26 '15 at 10:56
• It's more important now than it ever has been to be precise with numeric terminology. – Hot Licks Mar 26 '15 at 11:39

No you can't. Take for example this set of numbers: {1, 545, 42, 2640}

In that set there are ten digits, but only four numbers.

545 is a number with three digits. However, if the digits were separated, i.e. 5, 4, 5, then you will have three digits and three numbers.

No, we cannot substitute digit with number.

The difference between a digit and a number is similar to the difference between an alphabet and a word which will always remain the way it has been.

Just like alphabetics make words, digits make numbers.

• Why do people say 'Write two hundred and fifty in numbers' then? – Edwin Ashworth Mar 26 '15 at 14:49
• @EdwinAshworth dunno, but that equals 200.50 (and it should be numerically). – Mazura Mar 27 '15 at 2:21
• @EdwinAshworth : Normally people could say it but I am sure that is not mathematically correct. This would otherwise resolve the very use of digits. We always say the digit at nth place but never number at nth place. Just doesn't sound right to the ears. – Veronica Diamond Mar 27 '15 at 7:04
• English usage isn't as well-defined as maths usage (and there are even disputes over terminology amongst mathematicians, and certainly amongst maths teachers). "[We] cannot substitute 'digit' with 'number' " is not quite the whole story, but the two terms overlap in usage only to a small degree. – Edwin Ashworth Mar 27 '15 at 12:14
• @EdwinAshworth : yes, you are right and you definitely know better.. but Silvia wants to know if it is appropriate to use. I would like to advise that it's better to keep them separate. – Veronica Diamond Mar 30 '15 at 4:47
• One of the ten Arabic number symbols, 0 through 9.
• A member of any of the following sets of mathematical objects: integers, rational numbers, real numbers, and complex numbers. These sets can be derived from the positive integers through various algebraic and analytic constructions.

1: is both a digit and a number (a single digit number).

326: is a number made up of three digits, a three-digit number.

As for you example 2, 3, 4 and 5 are four numbers (single digit numbers). To sum them up I'd refer to them as numbers rather than digits.

• @terdon - I fixed it!! – user66974 Mar 26 '15 at 20:57