(1)
40/2.5
=40*4/(2.5*4)
=40*4/10
=4*4
=16
(2)
16分之13*(13分之9*17-13分之9)
=(13/16)*(9*17/13-9/13)
=(13/16)*(9/13)*(17-1)
=(9/16)*16
=9
(1)
40/2.5
=40*4/(2.5*4)
=40*4/10
=4*4
=16
(2)
16分之13*(13分之9*17-13分之9)
=(13/16)*(9*17/13-9/13)
=(13/16)*(9/13)*(17-1)
=(9/16)*16
=9