Question

用简便方法计算下列各题：9.8x2.5= 1.25x64= 10.1x8.5=

Answer 1

9.8x2.5

=(10-0.2)x2.5

=10x2.5-0.2x2.5

=25-0.5

=24.5

1.25x64

=1.25x8x8

=10x8

=80

10.1x8.5

=(10+0.1)x8.5

=10x8.5+0.1x8.5

=85+0.85

=85.85

祝学习进步,望采纳~