This type of challenge has been described as flooding the web in recent times, partly because the format taps into a familiar anxiety — the nagging feeling that you may have forgotten something you were once taught in school.
The appeal is straightforward: the problem uses only basic arithmetic, requires no calculator, and can be solved in seconds — if you remember one specific rule.
Why the wrong answers feel so convincing
The trap is intuitive. Reading the expression left to right — the way we read a sentence — many people first add 40 + 40 to get 80, then multiply by 0 to get 0, then add 1 to arrive at 1. It feels logical, but it is wrong.
Others may reason that multiplying anything by zero wipes out the entire expression, landing on 0 or 1. Both paths ignore the rule that governs the correct sequence of calculations.
The error is not a sign of poor intelligence — it reflects how naturally the brain defaults to reading numbers in order, rather than pausing to apply a mathematical hierarchy.
A school rule, not a trick
The order of operations — PEMDAS or BODMAS depending on the country — is a standard part of middle and high school mathematics curricula worldwide. It establishes a fixed hierarchy for calculations so that any given expression has only one valid result, regardless of how it is read left to right. Without this convention, the same equation could produce multiple different answers.
