tính giá trị :
A=\(\frac{2^{19}\cdot27^3-15\cdot\left(-4\right)^9\cdot9^4}{^{6^9\cdot2^{10}+\left(-12\right)}^{^{10}}}\)
B= \(\left(\frac{1}{2^2}-1\right)\cdot\left(\frac{1}{3^2}-1\right)...\left(\frac{1}{98^2}-1\right)\cdot\left(\frac{1}{99^2}-1\right)\)