问题
解答题
19+199+1999+19999+199999.
答案
19+199+1999+19999+199999,
=(20-1)+(200-1)+(2000-1)+(20000-1)+(200000-1),
=20+200+2000+20000+200000-5,
=222220-5,
=222215.
19+199+1999+19999+199999.
19+199+1999+19999+199999,
=(20-1)+(200-1)+(2000-1)+(20000-1)+(200000-1),
=20+200+2000+20000+200000-5,
=222220-5,
=222215.