1, my mother and I went to buy oranges. A kilo of oranges is 1.8 yuan. My mother bought 4.5 kilos, which should be 8. 1 yuan, but the clerk was too careless to figure out that it was 9 yuan money. I calculated it again with my brain, and my aunt was wrong.

I said, "Auntie, 1.8 times 4.5 equals 8. 1 yuan! How can it be nine dollars? " "Well, that's right." Aunt said, and then found her mother's ninety cents.

My father asked me a question, which is heavier, one kilogram of cotton flowers or one kilogram of iron? I said, "Iron is heavy." "Why?" Dad said. I said, "No, it should be the same weight." "Wrong, in general, iron is heavy, because the density of iron is large and the volume is small, and the buoyancy is small, so iron is heavy. In a vacuum environment, it is as heavy. " Dad said.