题目内容
估算. 91÷30≈ |
164÷20≈ | 160÷19≈ |
80÷38≈ | 633÷70≈ | 810÷89≈ |
分析:在除法估算中一般要根据“四舍五入”法,把被除数看作是能被,除数整除的整十,整百,或几百几十…的数来进行计算,据此解答.
解答:解:(1)91÷30,
≈90÷30,
=3;
(2)164÷20,
≈160÷20,
=8;
(3)160÷19,
≈160÷20,
=8;
(4)80÷38,
≈80÷40,
=2;
(5)633÷70,
≈630÷70,
=9;
(6)810÷89,
≈810÷90,
=9.
≈90÷30,
=3;
(2)164÷20,
≈160÷20,
=8;
(3)160÷19,
≈160÷20,
=8;
(4)80÷38,
≈80÷40,
=2;
(5)633÷70,
≈630÷70,
=9;
(6)810÷89,
≈810÷90,
=9.
点评:在作估算时,一般要根据“四舍五入”法,把数看作整十,整百,整千…的数来进行计算.
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