求教数学巧算题

问题描述:

求教数学巧算题
48x25x67=?
{125x6}x16=?
299x99+99=?
404x25=?
12x25x70=?

48x25x67=8x4x25x67=(4x25)x(8x67)=100x536=53600(125x6)x16=(125x6)x8x2=(125x8)x6x2=1000x12=12000299x99+99=299x99+1x99=(299+1)x99=300x99=29700404x25=(400+4)x25=400x25+4x25=10000+100=1010012...