脱式计算。（能简算的要简算）（

脱式计算。（能简算的要简算）+t2S/~/y

（1）72-16.8÷0.4 +2.1+t2S/~/y

算式：提示+c-|:y+Z+t2S/~/y

=6i+`:X+t2S/~/y

（2）23.6×0.75+0.25×23 .6+t2S/~/y

算式：提示)k:z2X)K4R0?+t2S/~/y

=8c1f:T)D+@*c+t2S/~/y

（3）（2.3÷0.46-4.5）÷0.25+t2S/~/y

算式：提示5D:c(Y6s:Q+t2S/~/y

=)i'S7m3H0{0K8[/q+t2S/~/y

（3）37.2÷ [54.7-105.4 ×（0.45 ÷ 0.9）]+t2S/~/y

算式：提示-r9A4N+N3r1C/s+t2S/~/y

=6y*e+A'C+Y5]+t2S/~/y