数学题——简算简算：9999乘以7778+3333乘以6666=5.6乘69.32+138.64乘0.05+693.2乘

9999*7778+3333*6666
=9*1111*(7*1111+1)+3*1111*6*1111
=(63+18)*1111*1111+9*1111
=81*1111*1111+9*1111
=9*1111*(9*1111+1)
=99990000
5.6*69.32+138.64*0.05+693.2*0.43
=5.6*69.32+69.32*2*0.05+69.32*4.3
=69.32*(5.6+0.1+4.3)
=693.2
小朋友,下次 作业要自己做