Question

七分之六减去九分之一加上八分之七的脱式计算怎么算

七分之六减去九分之一加上八分之七的脱式计算怎么算

Answer 1

这样写行不行，原式=1-1/7-1/9+1-1/8
=2-1/7-1/8-1/9（然后后面通分）
＝2-（9×8+9×7+8×7）/7×8×9
=2-191/504
=（504×2-191）/504
=817/504

Answer 2

6/7-1/9+7/8
=1-1/7-1/9+1-1/8
=2-(1/7+1/8+1/9)
=2-(7+8+9)/(7×8×9)
=2-24/(72×7)
=2-24/(24×3×7)
=2-1/21
=40/21

Answer 3

6/7-1/9+7/8
=(54-7)/63+7/8
=47/63+7/8
=(47*8+63*7)/(63*8)
=817/504

Answer 4

6/7 -1/9 + 7/8
=432/504 -56/504 +441/504
=（432-56+441）/504
=817/504

Answer 5

就是这样做的