Number of Significant Figures in Result of Addition or Subtraction/Examples/3.16 + 2.7

Example of Use of Number of Significant Figures in Result of Addition or Subtraction

$3 \cdotp 16 + 2 \cdotp 7 = 5 \cdotp 9$

We have that:

the leftmost significant figure $d_m$ of $3 \cdotp 16$ is the $10^{-2}$ position

the leftmost significant figure $d_n$ of $2 \cdotp 7$ is the $10^{-1}$ position.

the leftmost significant figure of $3 \cdotp 16 + 2 \cdotp 7$ is the rightmost of $10^{-2}$ and $10^{-1}$, that is $10^{-1}$.

$\ds 3 \cdotp 16 + 2 \cdotp 7$

$=$

$\ds 5 \cdotp 86$

by calculation

$\ds $

$=$

$\ds 5 \cdotp 9$

to the nearest $10^{-1}$

$\blacksquare$