Question

2. Find the greatest number of 6 digits which is a perfect square
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Answer 1

Explanation:

Let x² be the largest six-digit perfect square. 

The largest six-digit number is 999,999, so 

x² ≤ 999,999. 

You know that 1,000² = 1,000,000, which is only 1 more than 999,999, so x² must be the next smaller square, which is (1,000 - 1)². 

(1,000 - 1)² = 999² = 998,001