用2、4、5、8、0这五个数字组成的五位数中,改写成万作单位而且得数约等于5万的数有（）个
50248,50284,50428,50482,50842,50824；52048,52084,52408,52480,52840,52804；54250,54205,54028,54082,54802,54820；45280,45208,45028,45082,
45820,45802；48025,48052,48250,48205,48502,48520.共30个