问题 解答题
口算:
19+19+19+19+19+19+19+19+19+19=______
55+55+55+…+55
100
=______×______=______.
答案

19+19+19+19+19+19+19+19+19+19=19×10=190;

55+55+55+…+55
100
=55×100=5500.

故答案为:190;55,100,5500.

单项选择题
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