题目内容
笔算并写出验算过程. 508+392= | 637-268= |
解:508+392=900;

验算:

637-268=369.

验算:

分析:(1)在计算508+392时,注意数位对齐;在验算时,用得出的结果减去392看看是否等于508,或用得出的结果减去508,看看是否等于392;
(2)注意数位对齐,在验算时,用得出的结果加上减数看看是否等于被减数即可.
点评:在计算这两题时,应注意数位对齐;在验算时,根据加法是减法的逆运算进行验算.

验算:

637-268=369.

验算:

分析:(1)在计算508+392时,注意数位对齐;在验算时,用得出的结果减去392看看是否等于508,或用得出的结果减去508,看看是否等于392;
(2)注意数位对齐,在验算时,用得出的结果加上减数看看是否等于被减数即可.
点评:在计算这两题时,应注意数位对齐;在验算时,根据加法是减法的逆运算进行验算.

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