10×20=____ 1-0.2=____ 6.5+3.4=____ 0.3 +1.8=____
9.28+0.7=____ 8.9-7.8=____ 8.9-1.9=____ 410+610= ____
桌子上有一个天平,天平左右两边各有一个可以滑动的托盘,天平的臂上各有几个相等的刻度.现在要把1克,2克,3克,4克,5克五个砝码放在天平上,且使天平左右两边保持平衡,该怎样放?
You'd better computer games for a long time.