well I would write this as a fraction. :D
.1 is equal to 1/10 and .1and .10 is equal to 10/100
so the amount of zeros on the bottom = the amount of numbers past the decimal point.
so you would have
\(6 \frac{371}{1000}\)
then you multiply the whole number by the denominator, and add it to the numerator
\(6*1000=6000\)
\(6000+371=6371\)
now you put that number over the original denominator.
\(\frac{6731}{1000}\)
