X is an odd number
x+2 is also odd (consider the example x = 3 so x+2 = 3+2 = 5). Adding 2 to any odd number is always odd
Similarly, so is x+6 (since we have x+2+2+2).
And so is x+10 (x+2+2+2+2+2).
So every value in this list is an odd number. The middle most values are x+2 and x+6 which are both odd.
Adding any two odd numbers together yields an even number. For example 3+5 = 8. Divide this even number in half and we may or may not get an odd number (eg: 8/2 = 4 and 6/2 = 3)
So this statement is sometimes true
Let x = the unknown number
five more than a number = twice the number
x + 5 = 2x
5 = 2x - x
5 = x
( Balance method is used to solve )
substitution
x + 5 = 2x
5 + 5 = 2 x 5
10 = 10
answer : the unknown number is 5
