A simple maths problem that challenges people to solve a riddle using just one line has gone viral after being watched more than 39 million times.
TikTok user Karingendi shared a clip, handing the problem to three friends who work as engineers and setting them the task of solving it in under three minutes.
The piece of paper shows the number 100 stacked on top of another 100, and she says: "If you can turn this into 200 with one line, I'll give you whatever you want."
The friends try turning the paper round to look at the puzzle from different perspectives, and even accuse her of writing the question wrong, but ultimately appear to be unable to solve the sum using a single line as they demand more time.
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Thankfully, with seconds to spare, one of the engineers finds the answer she was hoping for by removing the mathematical logic altogether.
He simply puts a line through the first one to change it from a 1 into a T, so the problem instead reads Too 100.
Some people were relieved to finally have an answer to the problem, as one person commented to say: "He got it. You could see the light bulb go pff."
And the penny dropped for another viewer, who wrote: "OHHH YOU PUT A LINE OVER THE 1ST ONE TO MAKE IT 'TOO 100'."
But not everyone was satisfied with the answer, as a third argued: "Making the top 1 into a T makes 'too 1 hundred' not 'too hundred' there's no correct answer, it's BS."
And someone else joked: "She's not replying because she knew she did it wrong."