Mercury, Venus, and Earth are the three planets closest to the sun. Would their combined distance from the sun be greater or less than the distance from the sun to Neptune? Show your work and justify your answer.

No, see below for explanation

Explanation:

Distance from Sun to Mercury = 57.91 million km

Distance from Sun to Venus = 108.2 million km

Distance from Sun to Earth = 149.6 million km

So their combined distance from the sun is = ( 57.91 + 108.2 + 149.6 ) million km = 315.71 million km

Distance from Sun to Neptune = 4.495 billion km

Convert this distance to millions = 4.495 * 1000 million km

= 4495 million km

It is clear that combined distance of Mercury, Venus & Earth from the Sun is much less than the distance from the Sun to Neptune