It also has an association with American basketball star LaMelo Ball, because of his impressive height of 6 feet 7.
It means “nothing” and can be used to suggest that a person, or something, is “average”.
But it really took off when Taylen Kinney, a 17-year-old basketball player from Atlanta, was asked to rank his Starbucks drink, according to the New York Times.
“Her maths teacher counts up to 5 and then waits for the kids to continue counting with ‘6...7’ and then they all laugh.”
A teacher from Sydney’s eastern suburbs says the teachers at her school have a good handle on keeping kids contained.
“Being playful with the children actually helps keep it at bay,” the Year 5 teacher told Kidspot.
She’s even found ways to incorporate it into her teaching methods.
“I have said, ‘we are reading from page 6 and 7,’ and done the hand action, let everyone have a laugh, then returned to the task,” she shared.
“I have organised a little writing challenge for the last day of school. In 6-7 minutes, write an explanation of what 6-7 means, how it originated and how it is used. You must write it in 67 words. No more, no less.”
A second teacher from New South Wales initially tried to make light of it.
“I tried to embrace it. You know, ‘what’s the answer to this question’ as a math teacher. ‘Oh my God? 67.’ Now I’ve like, full-on banned it because it just annoying that it brings nothing to the conversation,” she revealed.
“It’s that whole thing of the brain rot. They can’t explain what it means ... That’s my two cents. That’s my 67 cents!”
However, some teachers in the US and the UK, where the trend is currently more prolific, have described the situation as a “nightmare”.
“I’m an 8th grade teacher and I am so done hearing it that I just banned it from my classroom,” one wrote on Reddit.
“It was funny at first, but now it continually interrupts my class,” raged another.
Sign up to Herald Premium Editor’s Picks, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week’s best features, interviews and investigations. Sign up for Herald Premium here.