原式=(12-0.1)×9.5+23.8×1/4 =12×9.5-0.95+5.95 =12×9.5+5 =(10+2)×9.5+5 =95+2×9.5+5 =119
原式等于11.9×(10-0.5)+23.8×(1÷4)=11.9×10-11.9×0.5+23.8×1÷4=119-5.95+5.95=119