10袋大米,以每袋50千克为准:超过的千克数记作正数,不足的千克数记作负数,称重的记录如下:+0.5,+0.3,0,﹣0.2,﹣0.3,+1.1,﹣0.7,﹣0.2,+0.6,+0.7.
10袋大米共超重或不足多少千克?总重量是多少千克?
解:(+0.5)+(+0.3)+0+(﹣0.2)+(﹣0.3)+(+1.1)+(﹣0.7)+(﹣0.2)+(+0.6)+(+0.7)
=1.8(千克),
50×10+1.8=501.8(千克).
答:10袋大米共超重1.8千克,总重量是501.8千克.
补全对话。
A: ____(What/Where) are you going to do tomorrow?
B: I'm going to have ____(a/an) English lesson.
A: What are you going to do in your lesson?
B: We're going to draw some pictures in Renmin Park.
A: That ____(sound/sounds) great! I'm going to ____(see/ read)a film tomorrow.
B: Have a good time!
A: You too. I have ____(do/to do)my homework now. Bye.
B: OK. Bye.
在遇到巨大声响时,迅速张开口或闭嘴堵耳,这样做目的是( )。
求证: