Unless you're in a job which deals with numbers, many of us adults have left our basic math skills in days far behind us - leaving lots of parents scratching their heads while homeschooling over lockdown.
That has certainly been proven by one pesky Year 2 maths question which is stumping adults around the world, including Australian radio host Jackie 'O' Henderson.
She was left bamboozled by the question, which was posed by listener Liam upon calling into the KIIS FM radio show she shares with Kyle Sandilands.
"I've only ever seen a couple of people get it, but it's so simple; it's really not hard," he said, according to News.com.au.
The question is as follows:
A bat and a ball cost $1.10. The bat costs one dollar more than the ball. How much does the ball cost?
If you guessed 10c you're not alone - Henderson also guessed it, and was reportedly "stunned" to find she was incorrect.
"Jeez I can't understand, because you've spent $1.10, so there's only $1.10 spent, if it's a dollar more," she said.
The right answer?
The ball cost 5c. The bat, at $1.05, comes in at a dollar more.
The radio show posted the question to their Instagram, where it baffled listeners.
"That took me way longer than it should have!" one person commented.
"That hurts my brain," added another.
"My son is in Year 2 and no way he would get this," another commented. "I'm an accountant and it took me way longer than it should have."
An unofficial quiz of reporters in the Newshub newsroom saw only one person get it right, while about seven others all guessed the 10c answer.
But if you also guessed incorrectly, don't worry. According to behavioural economist Daniel Kahneman's book, Thinking, Fast And Slow, more than 50 percent of students from top US universities MIT, Princeton and Harvard also get the answer to the question wrong.