the sum of a & b is twice as big as n

That statementcan be written as the equation
(a+b) = 2 n

Are there any more parts to your question?

It is not possible to say what a, b or n is, exactly. The equation is a relationship between the three numbers.

To find the value of one variable in terms of the other two, you would need more information or additional equations.

For example, if you're given the value of 'a' or 'b', you can substitute it into the equation to solve for the other variable.

If you're given the value of 'n', you can rearrange the equation to solve for 'a' or 'b'.

Let's go through a couple of examples:

Example 1: Finding 'a' if you know 'b' and 'n'
Given: b = 5 and n = 3
Substituting these values into the equation:
(a + 5) = 2(3)
a + 5 = 6
Subtracting 5 from both sides:
a = 1

So, when b = 5 and n = 3, a would be equal to 1.

Example 2: Finding 'b' if you know 'a' and 'n'
Given: a = 4 and n = 2
Substituting these values into the equation:
(4 + b) = 2(2)
4 + b = 4
Subtracting 4 from both sides:
b = 0

So, when a = 4 and n = 2, b would be equal to 0.

Remember, these examples assume that you already have values for 'b' and 'n', or 'a' and 'n'. If you have different information, you can adapt the steps accordingly.