3.4x5.6+4.8x2.2=3.4x7x0.8+0.8x6x2.2=23.8x0.8+0.8x13.2=(23.8+13.2)x0.8=37x0.8=30x0.8+7x0.8=24+5.6=29.6 或者=（2.4x5.6+1x5.6)+2.4x2x2.2=2.4x5.6+5.6+2.4x4.4=2.4x(5.6+4.4)+5.6=2.4x10+5.6=24+5.6=29.6
