Give an order-of-magnitude estimate for the ratio of the electric force between two electrons 1m apart to the gravitational force between the electrons.

Without using a calculator, estimate the value of the following expression. Then compare your estimate value found using a calculator.

$\frac{243}{43}$

Without using a calculator, estimate the value of the following expression. Then compare your estimate value found using a calculator.

$2.80\times 1.90$

Without using a calculator, estimate the value of the following expression. Then compare your estimate value found using a calculator.

$312\times \frac{480}{160}$

Without using a calculator, estimate the value of the following expression. Then compare your estimate value found using a calculator.

$\frac{8.99\times {10}^9\times 7\times {10}^{-16}\times 7\times {10}^{-6}}{{\left(8\times {10}^2\right)}^2}$

Without using a calculator, estimate the value of the following expression. Then compare your estimate value found using a calculator.

$\frac{6.6\times {10}^{-11}\times 6\times {10}^{24}}{{(6.4\times {10}^6)}^2}$