# Why do we add an error of 0.1 to a measurement by an instrument of least count 0.1

If the measuremnt comes between 2.3 and 2.4 why do we write as 2.3 ± 0.1. Why can't we write it as 2.35 ± 0.05. I understand this gives a wrong idea about precision, but why not create a new convention?

• That seems strange to me. I'd write such a measurement in the way you suggest: $2.35 \pm 0.05$. See physics.stackexchange.com/q/523669/123208 BTW, there is another convention: parenthesis notation. Jun 3, 2021 at 7:08
• that's the way my book writes it Ncert physics class 11 india Jun 3, 2021 at 7:36
• I suppose a case could be made for writing $2.35 \pm 0.1$, but I can't see how they get $2.3 \pm 0.1$. Perhaps you should discuss this with your teacher. I don't want to give you advice that clashes with your school syllabus, and that could cause you to lose marks in your homework or exams. Jun 3, 2021 at 8:49
• @JahanZaib Hello! I study in CBSE class 11. Can you please put the complete question, or the question number/page number from NCERT textbook/exemplar. (I am also doing some numerical problems related to error analysis for a while.)
– user279106
Jul 4, 2021 at 2:24