FoundationNumeric answerFree solution
Two numbers sit just below a hundred. Compute .
Answer with a number. Fractions, powers and expressions like 23/6 or C(52,5) are read correctly in practice.
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Answer
Use the base-100 method. The deficits from are and . Cross-subtract either deficit from the other number, (or ), which gives the hundreds. The product of the deficits, , gives the last two digits. So . It works because , and it is the fastest route for any pair of numbers just below a power of ten.
Worked solution
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Takeaway: Near a power of ten: cross-subtract for the front, multiply the deficits for the back.
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