(sqrt(a) - sqrt(b)) x 1/k for perfect squares a, b

The same question, asked 2 times: 18 Sep 2025 S1*, 18 Sep 2025 S3. Every wording below, oldest first.

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Question 1
18 Sep 2025 S1
52 $\left(\sqrt{7225} - \sqrt{1225}\right) \times \left(\frac{1}{5}\right)$
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Question 2
18 Sep 2025 S3
51 $\left(\sqrt{6400} - \sqrt{2401}\right) \times \left(\frac{1}{4}\right)$
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Question 3
18 Sep 2025 S3
52 $\left(\sqrt{5776} - \sqrt{4761}\right) \times \left(\frac{1}{2}\right)$
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