问题
填空题
用简便方法计算: (1)7.292-2.712=______; (2)
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答案
(1)原式=(7.29+2.71)(7.29-2.71)
=10×4.85
=48.5;
(2)原式=10002 (252+248)(252-248)
=10002 500×4
=500.
故答案为48.5;500.
用简便方法计算: (1)7.292-2.712=______; (2)
|
(1)原式=(7.29+2.71)(7.29-2.71)
=10×4.85
=48.5;
(2)原式=10002 (252+248)(252-248)
=10002 500×4
=500.
故答案为48.5;500.