What’s the difference between solving a whole number and a fraction?

There’s these two methods I saw but not sure when I should use them when I do stumble on a problem.

1 method: start by multiply the numerator towards the whole number and once u do then divide the numerator and denominator separately.

2 method: start by giving the whole number a 1 of the denominator and find the lCD of the fraction and start finishing the problem from either adding or subtracting.