I'm going to the library today. I need some ______ about trees.
一种计算机每秒可做4×108次运算,它工作3×103秒运算的次数为( )
如图所示,悬挂着的吊灯处于静止状态,与吊灯所受重力是一对平衡力的是( )
806×5=____
190×7=____
667×6=____