The cards show the masses of four planets in standard form. Arrange the planets from lightest to heaviest.

First compare the powers of 10: Mercury and Mars have $10^{23}$, Venus and Earth have $10^{24}$. Then compare the numbers in front: $3.3<6.4$ and $4.9<6.0$. Order: Mercury, Mars, Venus, Earth. (Looking only at 3.3, 4.9, 6.0, 6.4 ignores the powers.)