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998+1246+9989
=1000-2+1246+10000-11
=1000+10000+1233=12233

416×221÷17×34÷208
=416/208*221/(17/34)
=442/0.5
=884

4848÷202
=4848/101/(202/101)
=48/2
=24

7.341÷3.5×0-0÷13.2+8
=0-0+8
=8

47.5×84×37.5×0×26=0

6885.6785÷6.785×678.5
=6885.6785÷(6.785/678.5)
=6885.6785/0.01
=6885.6785*100

3.1+2.4+1.9+3.6
=(3.1+1.9)+(2.4+3.6)
=5+6
=11

4.2*99+4.2
=4.2*(99+1)
=4.2*100
=420

42/38
=2*21/2*19
=21/19

24*（3/8+5/6）
=24*3/8+24*5/6
=9+20
=29

9.7*1.25*0.8
=9.7*(1.25*0.8)
=9.7*1
=9.7

(7/9)*(5/11)+(5/11)*(2/9)
=(5/11)*(7/9+2/9)
=(5/11)*1
=5/11
=688567.85

1.24+0.78+8.76
=（1.24+8.76）+0.78

=10+0.78

=10.78

933-157-43

解 原式=933-（157+43）