六年级简便运算题目急求!

2个回答

  • 小学六年级数学总复习资料(六) 【简便计算】

    班级:姓名:

    一、口算下面各题.(23分)

    10-2.65= 0.9×0.08= 528-349= 6+14.4= 24÷0.04=

    12.34-2.3= 0÷3.8= 0.77+0.33= 7÷1.4= 67.5+0.25=7.2÷8×4= 5-1.4-1.6= 400÷125÷8= 1.9×4×0.5=

    80×0.125= 3× = 6 6= 2 -( + )= 10 2=

    3.2×7÷3.2×7= ( - )×12= 187.7×11-187.7= 1- 62.5%=

    二、写出下列每题在简便运算时所运用的定律或性质(12分)

    4 +3.2+5 +6.8 25×(8×0.4)×1.25 7 -(2 - )

    ( ) ( ) ( )

    ( + + )×72 93.5÷3 16÷2.5

    ( ) ( ) ( )

    三、用简便方法计算.(65分)

    1125-997 998+1246+9989 (8700+870+87)÷87

    125×8.8 1.3+4.25+3.7+3.75 17.15-(3.5-2.85)

    3.4×99+3.4 4.8×1.01 0.4×(2.5÷73)

    (1.6+1.6+1.6+1.6)×25 ( + - )÷

    12.3-2.45-5.7-4.55 2 + 0.125×0.25×64

    64.2×87+0.642×1300 78×36+7.8×741-7 17+ 8

    0.125× +0.5 2.42 +4.58 -43

    25÷100 4.25-3 -(2 -1 )

    (1)1.25*17.6+36.1/0.8+2.36*12.5

    1.25*17.6+36.1/0.8+2.36*12.5

    =(5/4)*17.6+36.1*(5/4)+23.6*(50/4)

    =176/8+361/8+236/8

    =773/8=96.625

    (2)7.5*2.3+1.9*2.5

    7.5*2.3+1.9*2.5

    =7.5*(1.9+0.4)+1.9*2.5

    =(7.5+2.5)*1.9+7.5*0.4

    =19+3 =22

    (3)2004/2003*2005

    2004/2003*2005

    =(2004/2003)*(2003+2)

    =2004+4008/2003

    (4)276*543-267/276+543*275

    276*543-267/276+543*275

    =543*(276+275)-267/276

    =543*551-267/276

    (5)17/51+ (68/1+51/2)*17

    17/51+ (68/1+51/2)*17

    后面的做不下去了,好像有一些没有简便方法,不知道你题目有没有抄错,你的68/1中的68是分子还是分母呀?应该是分母都对

    (6)(3.25-0.8*8/5)/(6又4/1-3.5)

    是6又1分之4吗?应该是6又4分之1吧

    1)五十二又二十五分之十一×79.45+159×47.56+七十九又二十分之十一×52.44

    =52.44×79.45+159×47.56+79.55×52.44

    =52.44×(79.45+79.55)+159×47.56

    =52.44×159+159×47.56

    =159×(52.44+47.56)

    =159×100

    =15900

    3)2002+2001-2000-1999+1998+1997-1996-1995+……+2+1

    =(2002-2000)+(2001-1999)+(1998-1996)+(1997-1995)+……+(6-4)+(5-3)+2+1

    =2+2+2+2+……+2+2(从3-2002共2000个数,所以有1000个2)+2+1

    =1000×2+2+1

    =2003

    4,5两题均用到一个转换式1/(A×B)=1/(B-A)×(1/A-1/B)

    如1/15=1/(3×5)=1/(5-3)×(1/3-1/5)=1/2×(2/15)=1/15可验证一下

    4)(1×2分之一)+(2×3分之一)+(3×4分之一)+……+(10×11分之一)

    =1/(1×2)+1/(2×3)+1/(3×4)+……+1/(10×11)

    =(1-1/2)+(1/2 - 1/3)+(1/3 - 1/4)+……+(1/10 - 1/11)

    =1-1/11

    =10/11

    5)三分之一+十五分之一+三十五分之一+六十三分之一+九十九分之一

    =1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+1/(9×11)

    =1/2×(1-1/3)+1/2×(1/3-1/5)+1/2×(1/5-1/7)+1/2×(1/7-1/9)+1/2×(1/9-1/11)

    =1/2×(1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11)

    =1/2×(1-1/11)

    =1/2×10/11

    =5/11

    6)一又二分之一-六分之五+十二分之七-二十分之九+三十分之十一-四十二分之十三+五十六分之十五

    (根据提示,1又1/2=1+1/2,+1/2+1/3=5/6……)

    =(1+1/2)-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)

    =1+ 1/2 - 1/2 - 1/3 + 1/3 + 1/4 - 1/4 - 1/5 + 1/5 + 1/6 - 1/6 - 1/7 + 1/7 + 1/8

    =1+1/8

    =9/8