简便计算：2.5x2.3+1.2+0.25

2.5*(2+0.3)+1.2+2.5*0.1
=2.5*(2+0.4)+2.4*0.5
=(2.5+0.5)*2.4
=7.2

7.15

=2.5×(2.3+1)+1.2
=2.5×(3+0.3)+1.2
=2.5×3+2.5×0.3+1.2
=7.5+0.75+1.2
=8.7+0.75
=9.45

原式=0.25X23+1.2X0.25
=0.25X（23+1.2）
=0.25X24.2
=0.5X0.5X2X12.1
=0.5X12.1
=6.05

2.5x2.3+1.2+0.25=0.25x2.3x10+0.25x1+1.2=0.25x(23+1)+1.2
=(1/4)x24+1.2=6+1.2=7.2

注意：用了两个代换：2.5＝10x0.25和0.25=(1/4)

2.5x2.3+1.2+0.25
=2.5(2.5-0.2)+1.45
=2.5^2-0.5+1.45
=2.5^2+0.95
=6.25+0.95
=7.20