A fiendishly difficult maths problem has left social media users baffled, with many divided over the correct answer. The puzzle, which originated from an Instagram post, asks: '3x3-33+3'. While it may appear straightforward, the solution requires careful application of the order of operations.
Many people initially solved the equation by working left to right: 3x3=9, 9-33=-24, -24+3=-21. However, this is incorrect due to the rules of BIDMAS (Brackets, Indices, Division, Multiplication, Addition, Subtraction), also known as PEMDAS in the US. According to this convention, multiplication and division must be performed before addition and subtraction.
Applying BIDMAS correctly: first, perform the multiplication: 3x3=9. Then, handle the division: 33+3 is not present; the expression is '3x3-33+3', so after multiplication, we have 9-33+3. Now, addition and subtraction are performed from left to right: 9-33=-24, then -24+3=-21. Wait—that gives -21, but many claimed the answer is 11. Let's re-evaluate: the original expression is '3x3-33+3'. If we interpret '33' as '3*3'? No, it's written as '33'. Perhaps the puzzle is '3x3-3÷3+3'? The source text mentions '3x3-33+3' but also later explains steps using division: '3 x 3 = 9 and 3 / 3 = 1'. This inconsistency suggests the actual puzzle might be '3x3-3÷3+3'. Indeed, the source says: 'Perform multiplication and division first: 3 x 3 = 9 and 3 / 3 = 1. Substitute: 9 - 1 + 3 = 11.' So the correct expression is likely '3x3-3÷3+3', yielding 11.
Another viral maths puzzle involved a cow transaction: 'I bought a cow for $800. I sold it for $1000. I bought it again for $1,100. I sold it again for $1,300. How much did I earn?' Answers ranged from $100 to $400. The correct answer, explained by Instagram user Visual Nostalgic, is $400. Breaking it down: first sale profit $200, second purchase at $1100 reduces net profit to -$900 (if considering cumulative), but final sale at $1300 gives total profit $400.
These puzzles highlight the importance of following mathematical conventions and careful step-by-step reasoning.
