31又5分之1乘8.1+4.37乘19+1.9乘87又2分之1=?
问题描述：
31又5分之1乘8.1+4.37乘19+1.9乘87又2分之1=?
答
=(131.2-100)×8.1+(43.7×1.9+1.9×87.5)
=131.2×8.1-100×8.1+(43.7+87.5)×1.9
=131.2×8.1-100×8.1+131.2×1.9
=131.2×(8.1+1.9)-100×8.1
=131.2×10-810
=1312-810
=502
答
原式
=31.2x8.1+4.37x19+1.9x87.5
=31.2x8.1+4.37x19+19x8.75
=31.2x8.1+(4.37+8.75)x19
=31.2x8.1+13.12x19
=3.12x81+(3.12+10)x19
=3.12x81+3.12x19+10x19
=3.12x(81+19)+10x19
=3.12x100+190
=312+190
=502