Move 2 lines (one short and the other long) from one side (either) to the other side of the = sign to make the equation correct. Cannot use "not equal to" sign. You must move 2 lines as stated. Some creative thinking may be needed.

some lines depicting 410=9/5


Think of letters

  • $\begingroup$ Are all lines supposed to be the same length? $\endgroup$ Jan 20, 2023 at 0:11
  • $\begingroup$ No. The lines are of the length as given in the image. Thanks $\endgroup$
    – RogerA
    Jan 20, 2023 at 12:42

2 Answers 2


Starting point

The Bekenstein-Hawking formula for the entropy of a black hole, $S$, in Planck units, is given by $$ S = A/4$$ where $A$ is the area of the event horizon.
We may rewrite this equation as $$4 = A/S$$ or perhaps $$4-0 = A/S$$

Given that, we move the following (highlighted) lines

enter image description here

To the opposite sides of the equals sign to give

enter image description here

  • $\begingroup$ "Move 2 lines (one short and the other long) from one side", but you moved from left and right side. is it okay like that? $\endgroup$
    – Oray
    Jan 23, 2023 at 14:40
  • 1
    $\begingroup$ @Oray My interpretation is that each line must move from one side to the other (but not necessarily originating from the same side). Although the phrasing in the question is a little ambiguous. $\endgroup$
    – hexomino
    Jan 23, 2023 at 14:45

4 - 0 = 9 - 5 That is, the 1 becomes a minus and the division also becomes a minus.

  • 2
    $\begingroup$ It says to move two lines from one side of the equality sign to the other. $\endgroup$
    – msh210
    Jan 20, 2023 at 6:02
  • $\begingroup$ The way I see it, the division sign should become the minus on the left side, and the 1 should become the subtraction side on the other one. $\endgroup$
    – user79541
    Jan 20, 2023 at 12:40

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