De Morgan's laws
Rewrite this condition without using not, so that it means exactly the same thing:
if not (x > 0 and x < 10):
print("out of range")Show hint
"Not (A and B)" is the same as "(not A) or (not B)". What is the opposite of x > 0?
Show solution
if x <= 0 or x >= 10:
De Morgan's laws say not (A and B) equals (not A) or (not B), and not (A or B) equals (not A) and (not B). The opposite of x > 0 is x <= 0, not x < 0. Getting that edge wrong is a classic off-by-one bug.
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