The word 'careful' means to pay attention to something as you do it - (to do it carefully)
The opposite of this would be not to pay attention to something you do as you do it - (to do it carelessly)
So the opposite of careful is careless
Here is a sentence : He was careful as he crossed the road and got to the other side OK, but she was careless as she crossed the road and was hit by a car.
Conscious means being generally awake and aware. The opposite of this would to be unconscious - someone who has been hit on the head and knocked out would be unconscious.
So the opposite of conscious is unconscious
To be conscious is to be aware of and responding to one's surroundings; awake.
Adding is the opposite of subtracting
If by "opposite" you mean its additive inverse, the answer is 0. If by "opposite" you mean its multiplicative inverse, for the number x, it will be (x+1/x).
opposite
If you mean hard as in the opposite of soft, then rigid, firm, adamatine. If you mean the opposite of easy, then difficult
The opposite prefixes for the word "conscious" are "un-" and "uncon-".
The verb form of "conscious" is "conscientious." It means to be careful, diligent, and guided by a sense of right and wrong.
Or cautious.
Be careful hat your wishes are, means that you should be conscious of what goes through your thinking. Thought most times can transform into action, and if it were negative thought, the consequence is also negative.
'Semi-conscious' means not fully conscious or awake.
The opposite of reckless would be cautious or careful.
Careful.
The opposite of careful with a C pronounced like an S is "careless."
careful
careful; responsible
Opposite for offhand: "calculated, careful, considered, deliberate, planned"
The opposite of mechanical (by machine) could be biological or natural.The opposite of mechanical (perfunctory, without thought) could be conscious, considered, or thoughtful.Where mechanical has the connotation automatic, the opposite would be manual.