An insect crawls back and forth from a far point on a straight road, assuming that the right crawling behavior is positive and the left crawling behavior is negative, and the crawling distance in turn is (unit cm).

+2 -4 +5 -2.5 -5 +4.5

Please calculate whether the insect finally returns to the origin 2-4+5-2.5-5+4.5=0.

A warehouse used to store 250 tons of products, and the entry and exit within one week are as follows: the warehousing is positive and the outbound is negative.

150 -30 -65 50 - 150 -35 -20

On the seventh day, how many of these products were stored in the warehouse?

150-30-65+50-150-35-20 =-100 250-100 =150 On the seventh day, the product was put into storage.