125×235-26×235+235 238×99 2+4+6+8···+80 2000-3-6-9···-51-54
1个回答

125×235-26×235+235

=235×(125-26+1)运用了乘法分配律

=235× 100

=23500

238×99

=238×(100-1)

=238×100-238

=23800-238

=23562

2+4+6+8···+80

=(2+80)×40÷2

=82×20

=1640

2000-3-6-9···-51-54

=2000-(3+6+9…+51+54)

=2000-(3+54)×18÷2

=2000-57×9

=2000-513

=1487