\(\frac{20^{20}.3^{40}.6^{20}}{12^{50}.3^{15}}\)=\(\frac{2^{20}.3^{40}.2^{20}.3^{20}}{3^{50}.2^{100}.3^{15}}\)=\(\frac{2^{40}.3^{60}:\left(2^{40}.3^{60}\right)}{2^{100}.3^{65}:\left(2^{40}.3^{60}\right)}\)=\(\frac{1}{2^{60}.35}\)

có cuộc thi nhưng dành cho lp 6 ak