I knew a guy in college that had a different flavor of candy for each class. He’d suck on a candy while studying or doing his homework, and again at test time. He swore by it. His grades were decent enough, but I wouldn’t call it definitively true.
When dealing with algebra, my math teacher never let us say -x as “negative x”, it was always “the opposite of x”. Because, X might be a negative number, and -(-2) would be the opposite of negative 2 = positive 2. It also helps to think of it as its own operator (like * or +) that automatically changes the sign. Since you can multiply in any order: -2*-2 is the same as "the opposite of the opposite (double negative) of 2*2. Finally, 2*2=4. The opposite of that is -4, and the opposite of that is 4. Two negatives multiplied become positive.
I knew a guy in college that had a different flavor of candy for each class. He’d suck on a candy while studying or doing his homework, and again at test time. He swore by it. His grades were decent enough, but I wouldn’t call it definitively true.