900×15 900÷15
=(1000-100)×15 =(900×2)÷(15×2)
=1000×15-100×15 =1800÷30
=15000-1500 =60
=13500
900÷3÷5=60
900÷15
=(900×6)÷(15×6)
=5400÷90
=60
900÷15
=60×(15÷15)
=60
_(:_」∠)_
要用除法裂数是的