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number theory junior
Problem
The numbers from to are arranged in a spiral pattern on a square grid, beginning at the center. The first few numbers have been entered into the grid below. Consider the four numbers that will appear in the shaded squares, on the same diagonal as the number How many of these four numbers are prime? 
(A)
(B)
(C)
(D)
Solution
We fill out the grid, as shown below: From the four numbers that appear in the shaded squares, of them are prime: and
Final answer
D