简便方法计算 1、412*81+11*925+537*19 2、7.28-4.16+2.92-1.84+7.08+4.72
问题描述：
简便方法计算 1、412*81+11*925+537*19 2、7.28-4.16+2.92-1.84+7.08+4.72
3、2.5*0.72+36*0.172-0.072*11
4、4.2*12.5*0.25*16
5、8.5*2.3+1.8*1.5+0.5*15.5
答
1.412*81+11*925+537*19=(81+19)*412+(19+11)*125+800*11=41200+3750+8800=537502.7.28-4.16+2.92-1.84+7.08+4.72=(7.28+2.92)-(4.16+1.84)+(7.08+4.72)=10.2-6+11.8=(10.2+11.8)-6=22-6=163.2.5*0.72+36*0.18...3.2.5*0.72+36*0.182-0.072*11=(2.5-1.1)*0.72+36*0.172=1.4*0.72+3.6*(1+0.72)=(1.4+3.6)*0.72+3.6=5*0.72+3.6=3.6+3.6=7.23.2.5*0.72+36*0.182-0.072*11错了是3、2.5*0.72+36*0.172-0.072*11题目敲进去的时候敲错了 过程是正确的2.5*0.72+36*0.172-0.072*11=(2.5-1.1)*0.72+36*0.172=1.4*0.72+3.6*(1+0.72)=(1.4+3.6)*0.72+3.6=5*0.72+3.6=3.6+3.6=7.2