How do i calculate following equations?

These aren't equations, just expressions you have to evaluate.

In order to add two fractions that have different denominators, you need to express those fractions in terms of a common denominator by finding the LCM of all the denominators involved.

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For the first expression,

because 22 = 2 * 11 and 15 = 3 * 5 share no common divisors, so the LCM would be their product.

Mixed fractions should be rewritten as improper ones:

Now rewrite everything in terms of the common denominator:

and we can rewrite this as a mixed fraction, noting that 975 = 2 * 330 + 315:

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For the second expression,

because 14 * 32 = 448, but 14 = 2 * 7 and 32 = 2^5 already share one common factor of 2 that we can factor out from 448.

Then

Dividing by a fraction is the same as multiply by the reciprocal of the fraction by which you're dividing. In other words,

Noticing that 6216 = 9 * 672 + 168, we end up with

are you sure this is middle schools math? ?

for the points! : )