分数四则混合运算练习1: 3/7x+1/2x=13 (3/7+1/2)x=13(6/14+7/14)x=13 13/14x=13 x=14 x-1/5x=8/15 4/5x=8/15 x=8/15÷4/5 x=8/15×5/4 x=2/3 4x+5x=18/11 9x=18/11 x=18/11÷9 x=18/11×1/9 x=2/112: 1/7×6/13+8/13×1/7 = 1/7×(6/13+8/13) = 1/7×14/13 = 2/13 1/2÷4/5÷(2/9×3/8) = 1/2×5/4÷1/12 = 1/2×(5/4×12) = 1/2×15 |