Complete the following expression.

$4000$4000$=$= $\editable{}$ × $10^3$103

Given that $1$1÷$10$10 = $1\times\frac{1}{10}=1\times10^{-1}$1×110=1×10−1,

Express $7$7÷$10^2$102 in standard form form.

Use index laws to simplify $3\times10^5\times7\times10^2$3×105×7×102. Give your answer in standard form.