计算下列各题,能简便的要简便计算.
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计算下列各题,能简便的要简便计算. 618÷45+1620 | 1
(1)618÷45+1620,
=13 11 15+1620, =1633 11 15; (2)1 1 8÷( 1 4+2.5× 4 5), =1 1 8÷( 1 4+2), =1 1 8÷ 9 4, = 9 8× 4 9, = 1 2; (3) 6 7- 6 7×( 2 3+ 1 9), = 6 7×(1- 2 3- 1 9), = 6 7× 2 9, = 4 21; (4)2008÷2008 2008 2009, =2008÷ 2008×2009+2008 2009, =2008÷ 2008×2010 2009, =2008× 2009 2008×2010, = 2009 2010; (5)200.8×73-6.3×2008, =2008×7.3-6.3×2008, =2008×(7.3-6.3), =2008×1, =2008; (6)99-97+95-93+91-89+…+7-5+3-1, =(99-97)+(95-93)+(91-89)+…+(7-5)+(3-1), =2+2+2+2+…+2+2(25个2), =2×25, =50. |