Q.Find the gravitational force between the Sun and the Earth. Given Mass of the Sun = $1.99\times10^{30}$ kg, Mass of the Earth = $5.98\times10^{24}$ kg, the average distance between the Earth and the Sun = $1.5\times10^{11}$ m.

[!TLDR] $F=GM_{Sun}M_{Earth}/r^2$ with the given values gives $F\approx3.5\times10^{22}$ N. …

Using $F=\dfrac{GM_1M_2}{r^2}$ with $G=6.67\times10^{-11}$ N m^2/kg^2, $M_{Sun}=1.99\times10^{30}$ kg, $M_{Earth}=5.98\times10^{24}$ kg, $r=1.5\times10^{11}$ m:

Numerator: $GM_{Sun}M_{Earth}=6.67\times10^{-11}\times1.99\times10^{30}\times5.98\times10^{24}$. First $6.67\times1.99=13.27$, giving $1.327\times10^{20}$; then $1.327\times5.98=7.936$, giving $7.936\times10^{44}$.

Denominator: $r^2=(1.5\times10^{11})^2=2.25\times10^{22}$. …

Substitute the given masses and distance directly into $F=GM_1M_2/r …

Errors in tracking powers of ten across three multiplied large numbers -- best done by multiplying the coe …