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第70页

信息发布者：

$a$

$b$

$a$

$-$

$b$

$\div$

$c$

=(636+84)÷3

=720÷3

=240

=4500÷45−90÷45

=100−2

=98

$120\div 3 + 120\div 5 = 64$

$120\div (3 + 5) = 15$

$64\neq 15，$所以$a\div b + a\div c=a\div (b + c)$不

正确。

=2222×4+2222×4×19

=2222× (4+4×19)

=2222×80

=177760

=72×85+38×85−85×10

=85×(72+38−10)

=85×100

=8500

=51×102×78÷17÷34÷13 

=(51÷17)×(102÷34)×(78÷13) 

=3×3×6 

=54

=(1000+999−998−997)+(996+995−994−993)+

...+(4+3−2−1)

=4+4+...+4

=4×250

=1000

=2025×2026×(10001−10001)

=0

$7$

$62$

$220$

$45$