5+5+5+5+1
That is only 5 numbers being added. There can be no answer for six numbers for the following reasons:
The numbers are all odd.
Two odd numbers make an even number.
Two even numbers make an even number.
21 is odd.
Take 6 odd numbers and add them up in pairs.
Each pair of odd numbers gives an even number so there are 3 even numbers.
Even + Even + Even = Even.
So sum of any six odd numbers is even but 21 is not even.
It is not possible to make six odd numbers total an odd number, so this requires a little lateral thinking: 3 + 3 + 3 + 1 + 11, or you could invert one of the nines and make a six... 6 + 5 + 3 + 3 + 3 + 1...
Any pair of consecutive numbers will have an odd total. 10 and 12 are consecutive even numbers that total 22.
You can choose any three numbers that total 10, but the sum of any two of those numbers must be greater than the third number. For example, Isosceles triangles : 3,3,4 : 4,4,2 Equilateral triangle : 3⅓,3⅓, 3⅓ Scalene triangle : 2, 3½, 4½
The median of that would be any of the two numbers that are the same.
Irrational numbers are infinitely dense so that there are infinitely many irrational numbers between any to numbers. In fact, there are more irrational numbers between any two numbers than there are rational numbers in total!
I'm not sure if you are limited by purely addition or what the rules are so I have the following answer:Using only 6 numbers, but any function:3*5-5+9+1+1 = 21
3*3*3-(5+(5/5)) 9+3+3+5+1(to the power of 1) ...using 6 numbers logic fullfilled ...here in this answer v use the clause of using all given digits
Since it is axiomatic that six odd numbers MUST total an even number, you have to be "constructive" (ie cheat): 3 + 3 + 3 + 1 + 11 = 21, or even more "constructively", let one of the 9s slip so that it becomes a 6 and have: 6 + 5 + 3 + 3 + 3 + 1 = 21. I'm sure there are other equally effective ways of being "constructive"!
It is not possible to make six odd numbers total an odd number, so this requires a little lateral thinking: 3 + 3 + 3 + 1 + 11, or you could invert one of the nines and make a six... 6 + 5 + 3 + 3 + 3 + 1...
3 + 3 + 3 + 1 + 11 = 21
Any pair of consecutive numbers will have an odd total. 10 and 12 are consecutive even numbers that total 22.
Any number can be made up from those numbers.
There are more irrational numbers between any two rational numbers than there are rational numbers in total.
You can choose any three numbers that total 10, but the sum of any two of those numbers must be greater than the third number. For example, Isosceles triangles : 3,3,4 : 4,4,2 Equilateral triangle : 3⅓,3⅓, 3⅓ Scalene triangle : 2, 3½, 4½
The median of that would be any of the two numbers that are the same.
depens if the number can be used in any order
There isn't any. If there were, then the intersection would consist of all the numbers that are both rational and irrational, and there aren't any of those.