A brain teaser has left people across the internet scratching their heads – but far from a complicated algebraic puzzle, it’s just a simple addition sum leaving them bewildered.
Shared by self-professed ‘lover of mathematics’ Ganesh UOR on X/Twitter, the viral problem seems easy enough at first glance.
But as thousands take a stab at solving it, it’s becoming clear that this seemingly straightforward maths question is causing more confusion than anyone expected.
The problem reads: ‘You have 1000, add 40, add 1000, add 30, again 1000, add 20, add again 1000, and finally 10. What is the result?’
Sounds simple but in the comments, people are fiercely divided.
Some are adamant the answer is 5,000 – presumably adding one extra thousand somewhere along the way.
Others argue it’s 4,100 – the actual correct solution.
One user was quick to comment ‘5,000’ before second guessing themselves and posting a second comment that read ‘4,100’.
The apparently easy maths problem, involving only mental addition, has racked up thousands of comments
The more eagle-eyed among the maths fans are, instead, overcomplicating the question, tripped up by the colloquial wording.
BN O’Neil wrote: ‘If “again” and “and finally” are to be understood as additions, it’s 4,100, else 3,090.’
And Dennis said: ‘That’s 3,090. “Again” on its own doesn’t indicate a maths symbol.’
What’s catching people out? It seems it’s down to the way our brains instinctively group large numbers – particularly when we read them quickly.
When presented in this verbal format, we tend to mentally clump the thousands together and miscalculate the smaller numbers in between.
Users in the comments were divided, with some falling for the trap and others confused by the ambiguity of the wording
The sums can be completed like so to reach 4100:
1000 + 40 = 1040
1040 + 1000 = 2040
2040 + 30 = 2070
2070 + 1000 = 3070
3070 + 20 = 3090
3090 + 1000 = 4090
4090 + 10 = 4100
David Sims, spotting the trick, said: ‘There’s a temptation to jump to 5,000 that you have to be on guard against.’
This is not the first time the internet has been torn over primary-level math equations.
Just recently, users weighed on a basic problem that went viral for its difficulty – but only a handful were able to pull off the proper arithmetic.
In order to reach the correct answer, one has to follow PEMDAS – a concept typically taught in fifth or sixth grade under the Common Core Curriculum.
PEMDAS is an acronym for the order of operations to solve an equation.
Anything inside parenthesis (P) should be worked out first. Secondly, exponents (E) should be addressed.
Next should be multiplication and division (MD), but multiplication does not necessarily have to come before division.
The correct method is to address them from left to right as the are written in the equation.
Lastly, addition and subtraction (AS). When only those two operations remain, the sum can be solved from left to right because the order makes no difference.
Below is the equation, give it a try before reading on:
Damien Scott shared the math problem on X, sparking furious debate among commenters
Among X users who were not briefed with a math lesson before tackling the calculations, the most popular wrong answer was 5, which is the solution found when PEMDAS is ignored and the problem is just from solved left to right.
Applying PEMDAS, the first step is to multiply and divide because there are no parenthesis or exponents. After solving 3 x 3 and 3 ÷ 3, the equation becomes 9 – 1 + 3.
From there, some simple addition and subtraction reveals the final result of 11.
