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简算速算巧算1.25*5.6+2.25*3.699.99*0.8+11.11*2.82003*2003+2002*2002-2003*2002-2002*20011-2+3-4+5-6+……+99-100+101

题目详情
简算速算巧算
1.25*5.6+2.25*3.6 99.99*0.8+11.11*2.8
2003*2003+2002*2002-2003*2002-2002*2001
1-2+3-4+5-6+……+99-100+101
▼优质解答
答案和解析
1.25*5.6+2.25*3.6
=1.25*8*0.7+2.25*4*0.9
=7+8.1
=15.1
99.99*0.8+11.11*2.8
=100*0.8+0.01*0.8+2.8*10+2.*1+2.8*0.1+2.8*0.01
=80+0.008+28+2.8+0.28+0.028
=111.116
2003*2003+2002*2002-2003*2002-2002*2001
=2003*(2003-2002)+2002*(2002-2001)
=2003+2002
=4005
1-2+3-4+5-6+……+99-100+101
=1+(3-2)+(5-4)+(7-6)+……+(101-100)
=1+1+1+1+1+1+1+……+1+1+1+1(注:共有50个1)
=50*1=50