你好，很高兴能帮你解决问题！
1/8+1/4 1/2+1/5 1/3+4/5 4/3+2/5 7/8+1/2 2/3+1/2 3/7+4/5 8/9+1/5 1/4+1/2 3/4+1/5 1/2+4/9 5/8+3/4 2/5+3/8 1/6+1/5 2/5+1/6 3/5+3/4 2/3+2/5 1/7+1/8 5/7+5/8 4/9+5/7
（这些题有些答案是假分数）
7/8 ﹣1/2 4/7-1/2 3/2-1/3 4/9-1/3 5/8-1/2 8/9-3/4 6/7-4/5 1/2-3/8 1/2-3/5 3/4-1/6
3/7-1/2 2/5-1/2 3/4-5/6 7/9-3/8 3/5-3/7 4/5-4/9 2/7-2/9 1/8-1/9 1/4-1/5 1/3-1/7
（这些题有些答案是负分数)
1/2×4/6 1/7×2/9 3/7×4/5 2/3×5/8 7/9×6/7 4/5×3/4 1/8×7/9 2/7×1/4 3/8×4/9 2/9×3/4
3/8×4/7 1/8×4/5 2/9×3/7 4/9×1/7 2/7×2/5 4/9×1/8 7/9×2/5 3/4×1/9 4/3×3/4 2/9×9/2
4/5÷3/5 8/7÷8/9 4/5÷2/3 2/9÷4/9 1/8÷6/7 2/7÷3/4 8/9÷4/5 4/7÷2/9 1/9÷2/3 3/4÷6/7
3/8÷5/6 3/8÷2/5 3/7÷1/8 1/4÷3/8 4/7÷2/9 4/9÷3/7 1/2÷7/9 4/9÷5/8 2/5÷3/4 5/9÷5/7
好好学数学啊！
追问非常感谢