999…91997个9×999…91997个9+1999…91997个9的末尾共有_个0.
问题描述:
×
999…9 1997个9
+
999…9 1997个9
的末尾共有______个0.
1999…9 1997个9
答
999…9(1997个9)×999…9(1997个9)+1999…9(1997个9)
=999…9(1997个9)×999…9(1997个9)+999…9(1997个9)+1000…00(1997个0),
=[999…9(1997个9)+1]×999…9(1997个9)+1000…00(1997个0),
=1000…00(1997个0)×999…9(1997个9)+1000…00(1997个0),
=[999…9(1997个9)+1]×1000…00(1997个0),
=1000…00(1997个0)×1000…00(1997个0),
=100…00(1997×2=3994个0).
即末尾共有3994个0.
故答案为:3994.