原式=0.76×(7.8+2.2)=0.76×10=7.6
采纳谢谢
1;4.2×7.8+2.2×4.2, =(7.8+2.2)×4.2, =10×4.2, =42; 2;9.5×101, =9.5×(100+1), =9.5×100+9.5×1, =950+9.5, =959.5; 3;(8×3.82)×1.25, =8×3.82×1.25, =(8×1.25)×3.82, =10×3.82, =38.2; 4;0.125×72, =0.125×8×9, =1×9, =9.