What odd numbers can be used to fill the blanks? __ + __ + __ = 30.
Odd numbers can't be divided into two parts equally.
Answer: There’s no solution if we got no brackets to insert. We can solve such questions only by using brackets as other contributors mentioned, “sum of 3 odd numbers can’t be even”.
Let's see in detail
Let k be any real number.
So, (2k + 1) will be an odd number & 2k will be an even number.
Let n, m be some other random real numbers.
If we add (2k + 1), (2m + 1), (2n + 1) (all being odd numbers)
We get, 2k + 2m +2n + 3
We know that,
2k, 2m, 2n are even numbers.
So, 2k + 2m + 2n is even and when you add an odd number to an even number we get an odd number.