654+823-554怎么简算还有9+99+999+9999 23×100.2迅速回答
3个回答

654+823-554

=(554+100)+823-554

=554-554+100+823

=923

9+99+999+9999

=(10-1)+(100-1)+(1000-1)+(10000-1)

=10+100+1000+10000-1-1-1-1

=11110-4

=11106

23×100.2

=23×(100+0.2)

=23×100+23×0.2

=2300+4.6

=2304.6