递等式计算(能简算的最好要简便计算). 2.5×2.7-0.63÷21; 2.3×0.48+0.48×8.7-0.12×4; 23×2.2÷23+1.95; [64-(3.6+11.9)×0.3]÷25.

问题描述:

递等式计算(能简算的最好要简便计算).
2.5×2.7-0.63÷21;              
2.3×0.48+0.48×8.7-0.12×4;
23×2.2÷23+1.95;
[64-(3.6+11.9)×0.3]÷25.

(1)2.5×2.7-0.63÷21=6.75-0.03=6.72(2)2.3×0.48+0.48×8.7-0.12×4=2.3×0.48+0.48×8.7-0.48=(2.3+8.7-1)×0.48=10×0.48=4.8(3)23×2.2÷23+1.95=23÷23×2.2+1.95=2.2+1.95=4.15(4)[64-(3.6+11.9)...