From '536 Puzzles and Curious Problems' by Henry Ernest Dudeney.
Can you find two three-figure square numbers (no zeros) that, when put together, will form a six-figure square number? Thus 324 and 900 (the
squares of 18 and 30) make 324,900, the square of 570, only there it
happens there are two zeros. There is only one answer.
Note: by 'put together' Dudeney refers to concatenating the digits.
On 14/12/2025 13:06, David Entwistle wrote:
From '536 Puzzles and Curious Problems' by Henry Ernest Dudeney.
Can you find two three-figure square numbers (no zeros) that, when put together, will form a six-figure square number? Thus 324 and 900 (the squares of 18 and 30) make 324,900, the square of 570, only there it happens there are two zeros. There is only one answer.
Note: by 'put together' Dudeney refers to concatenating the digits.
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I make it
15 * 15 = 225
25 * 25 = 625
475 * 475 = 225625
From '536 Puzzles and Curious Problems' by Henry Ernest Dudeney.
Can you find two three-figure square numbers (no zeros) that, when put >together, will form a six-figure square number? Thus 324 and 900 (the >squares of 18 and 30) make 324,900, the square of 570, only there it
happens there are two zeros. There is only one answer.
Note: by 'put together' Dudeney refers to concatenating the digits.
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