Question

七乘十五分之八减七乘三十五分之十二加七乘六十三分之一十六减九十九分之二十乘七

Answer 1

原式等于7*(8/15 -12/35 + 16/63 -20/99)
=7*((4/3 -4/5) - (6/5 - 6/7) + (8/7 - 8/9) -(10/9 -10/11))
=7*(4/3 - 4/5 - 6/5 +6/7 +8/7 -8/9 -10/9+10/11)
=7*(4/3 -2+2-2+10/11)
=56/33

Answer 2

7x8/15-7x12/35+7x16/63-20/99x7
=7x( 8/15-12/35+16/63-20/99)
=7x(56/105-36/105+4/9-20/99)
=7x( 4/21+24/99)
=7x( 132/693+168/693)
=7x100/231
=100/33

追问

没用简便吗

追答

下面的方法简单，上面算错了，向二楼学习