How do you convert lightyears into miles?

Question

I know that 1.42 lightyears = 8.34746974 × 10^12 miles but how do I get that answer? How do I show my work?

Answer 1

multiply 186,282 (miles that light travels in 1 second) * M * H * D * Y, where:

M = # of seconds in a minute
H = # of minutes in an hour
D = # of hours in a day
Y = # of days in a year

Then express as scientific notation.

Answer 2

Divide both sides by 1.42, hence, 1 lightyear = that number divided by 1.42