GRE
x
3
The remainder when $$7^{13}$$ is divided by 10
7
($$\frac{2}{3}$$@$$\frac{2}{3}$$)@$$\frac{2}{3}$$
$$\frac{2}{3}$$@($$\frac{2}{3}$$@$$\frac{2}{3}$$)
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