Question

2.5*13+0.9 用简便方法计算

Answer 1

2.5*13+0.9
=2.5*12+2.5+0.9
=2.5*4*3+3.4
=10*3+3.4
=30+3.4
=33.4

Answer 2

2.5*13+0.9
=2.5*13+2.5*3/8
=2.5*（13-3/8）
=2.5*101/8
=303/10
=30.3

Answer 3

2.5×13＋0.9＝32.5＋1－0.1＝33.5－0.1＝33.4