一 0.25X72X4X72=(0.25X4)X72X72=1X72²=72²二 0.25X72X4X72=1/4X4X72X72=72X72=(72X7X10)+(72X2)=5040+144=5184方法:凑成1,把四个数相乘变成两个二个数相乘;再把二位数乘法变成一位数乘法,就方便心算了。
你好!0.25×72×4×72=(0.25×4)×72=1×72=72
0.25X4=100,72X72=5184,0.25x72x4x72=5184