The problem below (Moscow Puzzles #313) can be solved in more than 4 ways,

(each d1 by itself) - using different approaches.

**Find the number t and the digit represented by k in:**

[3*(230+t)]^2=492,k04

List your ways of solving it.

Mod 10, the equation becomes 9*t^2 = 4

Then t^2 must equal 6 mod 10,

so t can only be 4 or 6.

Substitute both values in [3*(230+t)}^2 and evaluate.

This leads to the result that t can only be 4