Câu trả lời:

\(8^4:8^2=8^2=64\)

\(7^6:7^3=7^3=343\)

\(25.4.8.5=\left(25.4\right).\left(8.5\right)=100.40=4000\)

\(40.10.5.6.7=\left(40.10\right).30.7=400.30.7=12000.7=84000\)