Question

_+_+_=30 (1,3,5,7,9,11,13,15) Use numbers from the bracket . You can repeat the term

Answer 1

You can't

Proof:
Let n = {1,3,5,7,9,11,13,15}

Now each number in n is of the form (2s+1) where s ={0,1,2,3,4,5,6,7}

_+_+_ =30
=> (2a+1) + (2b+1) + (2c+1) =30, where a,b,c belongs to s
=> 2(a+b+c) +3 =30
=>2(a+b+c) = 27

Not possible, since RHS is odd and LHS is even.

Answer 2

Use 15+13+(5-3)=30.
Or
Use 3!+11+13=30.
(3!=3*2=6).