(1)24.6+31.79+25.4, =24.6+25.4+31.79, =50+31.79, =81.79; (2)3.21-1.O5-1.7, =2.19-1.7, =0.46; (3)(0.5+0.25)×4, =0.5×4+0.25×4, =2+1, =3; (4)76-2.4÷0.08, =76-30, =46; (5)4÷[1-(0.8+0.12)], =4÷[1-0.92], =4÷0.08; =50; (6)2.46×9+9×7.54, =(2.46+7.54)×9, =10×9, =90. |