Question

6.9÷15+28.8÷7.5的简便脱式计算？

能简算吗？列式

Answer 1

6.9÷15+28.8÷7.5
=6.9÷15+28.8÷（7.5x2÷2)
=6.9÷15+28.8÷（15÷2)
=6.9÷15+28.8÷15x2
=6.9x1/15+28.8x1/15x2
=6.9x1/15+28.8x2x1/15
=(6.9+28.8x2)x1/15
=(6.9+57.6)x1/15
=64.5x1/15
=4.3
又 6.9÷15+28.8÷7.5
=6.9x1/15+28.8x1/7.5
=6.9x2/30+28.8x4/30
=(6.9x2+28.8x4)/30
=(13.8+115.2)/30
=129/30
=4.3

Answer 2

6.9÷15+28.8÷7.5
＝6.9÷7.5÷2+28.8÷7.5
＝3.45÷7.5+28.8÷7.5
＝(3.45+28.8)÷7.5
＝32.25÷7.5
＝4.3