Problem 4 · 2011 Math Kangaroo
Easy
Algebra & Patterns
custom-operation
My calculator has gone mad. If I want to multiply, it divides, and if I want to add, it subtracts. I type in \((12\times3)+(4\times2)=\). Which result will it give me?
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Answer: A — 2
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Hint 1 of 2
Replace every × with ÷ and every + with − before you compute.
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Hint 2 of 2
Evaluate (12÷3)−(4÷2).
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Approach: swap the operations as the broken calculator does
- The calculator turns × into ÷ and + into −.
- So (12×3)+(4×2) is actually carried out as (12÷3)−(4÷2).
- That gives 4−2 = 2.
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