Answer
$ 0.237~in$
Work Step by Step
We have $2$ numbered divisions on the barrel:
$2 \times 0.100~in = 0.200~in$.
We have $1$ small division on the barrel:
$1 \times 0.025~in= 0.025~in$.
The head reading is $12$:
$12\times 0.001~in= 0.012~in$.
Thus, the total measurement is:
$0.200+0.025+0.012=0.237~in$
