Force of Mr. Andrade on the Moon

Question:
What is the force of Mr. Andrade standing on the surface of the Moon in lbf if he weighs 190 lb on Earth?

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GUESS Method

Given:
$W_{\rm Earth} = 190~\rm{lb} = 190 \cdot 4.44822~\rm{N} \approx 844.2~\rm{N}$
$g_{\rm Earth} = 9.81~\rm{m/s^2}$
$g_{\rm Moon} = 1.625~\rm{m/s^2}$

Unknown:
$F_{\rm Moon} = \rm{lbf}~?$

Equation:
$W = m \cdot g$
$m = \frac{W_{\rm Earth}}{g_{\rm Earth}}$
$F_{\rm Moon} = m \cdot g_{\rm Moon}$

Substitute:
$m = \frac{844.2}{9.81} \approx 86.1~\rm{kg}$
$F_{\rm Moon} = 86.1 \cdot 1.625 \approx 140~\rm{N}$

Solve:
$F_{\rm Moon} \approx 140~\rm{N}$

$F_{\rm Moon} = 140~\rm{N} \cdot \frac{1~\rm{lbf}}{4.44822~\rm{N}} \approx 31~\rm{lbf}$

The answer here is 31~\rm{lbf} because there are 2 sig digits on the input.

Question:
What is the force of Mr. Andrade standing on the surface of the Moon in lbf if he weighs 190. lb on Earth?

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GUESS Method

Given:
$W_{\rm Earth} = 190.~\rm{lb} = 190 \cdot 4.44822~\rm{N} \approx 844.2~\rm{N}$
$g_{\rm Earth} = 9.81~\rm{m/s^2}$
$g_{\rm Moon} = 1.625~\rm{m/s^2}$

Unknown:
$F_{\rm Moon} = \rm{lbf}~?$

Equation:
$W = m \cdot g$
$m = \frac{W_{\rm Earth}}{g_{\rm Earth}}$
$F_{\rm Moon} = m \cdot g_{\rm Moon}$

Substitute:
$m = \frac{844.2}{9.81} \approx 86.1~\rm{kg}$
$F_{\rm Moon} = 86.1 \cdot 1.625 \approx 140~\rm{N}$

Solve:
$F_{\rm Moon} \approx 140~\rm{N}$

$F_{\rm Moon} = 140~\rm{N} \cdot \frac{1~\rm{lbf}}{4.44822~\rm{N}} \approx 31.4~\rm{lbf}$

∴The force on Mr. Andrade on the Moon is approximately $\mathbf{31.4~lbf}$.

The answer here is 31.4~\rm{lbf} because there are 3 sig digits on the input.