So if I understand you correctly, you're saying that by intentionally making it more confusing people are more likely to select the correct answer more often? I suppose that could work, but that seems like an odd way to go about it.
If your goal is to stop people from getting the question wrong, then using words is the wrong way to go. Just give them the partially solved equation:
x = (1.1-1)/2. Solve for x.
Or to make it an actual question:
2x+1 = 1.1. Solve for x.
One step up again, though now its really getting confusing but more analogous to the original question:
(x+1)+x=1.1
Either way, I'd imagine you would be far more likely to get the correct answer.
To stop using a singular approximation word for what is not an approximation.
Can you explain how "greater in value" is a better choice than "more"? Or somehow less approximate?
Do you expect that someone capable of reading this question and doing the math is likely to get tripped up on the word "more" because they don't know its definition or meaning? If so, then do you expect a person who doesn't know the definition of "more" to know the definition of "greater"?
Does adding "in value" somehow fundamentally change how someone understands the question? What other thing is being referred to by "more" in the his question, if not "value"?
If you can't understand "more" on some fundamental level, why isn't "greater" just as confusing?
Why is "value" not confusing? Do you mean dollar amount? Personal value? Weight in gold?
I just don't get how a person who understands the question to begin with would be lead to the answer by your rephrase more often than the original.
edit
For the sake of completion:
You need a series of equations to make it precisely what the question originally asks with words:
y=x+1
y+x=1.1