Question

脱式计算（能简算的要简算）（12.5+7.5）÷0.25 &...

脱式计算（能简算的要简算）（12.5+7.5）÷0.25 2÷85×25413.1×56+5.6×69 2.8+[2.4÷（90-60）]．

Answer 1

（1）（12.5+7.5）÷0.25 
=20÷0.25
=80

（2）2÷

8

5

×

25

4

=2×

5

8

×

25

4

=7

13

16

（3）13.1×56+5.6×69
=131×5.6+5.6×69
=5.6×（131+69）
=5.6×200
=1120

（4）2.8+[2.4÷（90-60）]
=2.8+[2.4÷30]
=2.8+0.08
=2.88