Negative four squared is written with the sign inside the brackets, as (-4) * (-4). What is its value?

توضیح

The brackets draw the minus sign into both copies of the factor, so squaring multiplies two quantities that each lie below zero, the two directions cancel and the result is sixteen above zero. Answering with sixteen below zero holds the minus sign outside the squaring, where it has no partner left to pair with, and doubling the four instead of multiplying it by itself answers a different question.