①18.7-4.375-6.625
=18.74-（4.375+6.625）
=18.74-11
=7.74
②920÷40+23×50
=23+1150
=1173
③99.99×22.22+33.33×33.34
=33.33×（3×22.22）+33.33×33.34
=33.33×66.66+33.33×33.34
=33.33×（66.66+33.34）
=33.33×100
=3333
④

4

15

÷[（

5

7

-

3

14

）÷

3

4

]
=

4

15

÷[

1

2

×

4

3

]
=

4

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3

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=

2

5