二年级口算题:百内加减混合 (1)190 + 240 = (2)940 - 750 = (3)300 - 150 = (4)830 - 200 = (5)760 + 110 = (6)580 - 340 = (7)240 + 890 = (8)970 + 440 = (9)550 - 500 = (10)430 + 340 = (11)390 + 430 = (12)750 + 360 = (13)200 + 470 = (14)440 + 290 = (15)210 - 210 =