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1. 直接写出得数。
$0.5^{2}= $
$0.45+1.37= $
$80×0.3= $
$5y×y-y^{2}= $
$1.6-0.3= $
$1.6×4= $
$2.1×0.6= $
$10y-y+x= $
$1.46+0.64= $
$0.1×2.4= $
$1.2÷0.04= $
$10-a-a= $
$0.27÷9= $
$1.9×9= $
$2÷0.8= $
$8x+2x+10= $
$0.25×4= $
$0.53×3= $
$0.7÷0.35= $
$b-1.5-2= $
$4x+2x= $
$50n-18n= $
$6m-5.93m= $
$1.25×(x×0.8)= $
$5y-1.3y= $
$4.8c+2c= $
$4.8a÷0.8= $
$4.6c×c×2= $
$0.5a×2= $
$4.3y-0.9y= $
$4.5a×2= $
$0.9a×10+a= $
$0.5^{2}= $
$0.45+1.37= $
$80×0.3= $
$5y×y-y^{2}= $
$1.6-0.3= $
$1.6×4= $
$2.1×0.6= $
$10y-y+x= $
$1.46+0.64= $
$0.1×2.4= $
$1.2÷0.04= $
$10-a-a= $
$0.27÷9= $
$1.9×9= $
$2÷0.8= $
$8x+2x+10= $
$0.25×4= $
$0.53×3= $
$0.7÷0.35= $
$b-1.5-2= $
$4x+2x= $
$50n-18n= $
$6m-5.93m= $
$1.25×(x×0.8)= $
$5y-1.3y= $
$4.8c+2c= $
$4.8a÷0.8= $
$4.6c×c×2= $
$0.5a×2= $
$4.3y-0.9y= $
$4.5a×2= $
$0.9a×10+a= $
答案
0.25 1.82 24 4y² 1.3 6.4 1.26 9y+x 2.1 0.24 30 10-2a 0.03 17.1 2.5 10x+10 1 1.59 2 b-3.5 6x 32n 0.07m x 3.7y 6.8c 6a 9.2c² a 3.4y 9a 10a
2. 计算下面各题,能简算的要简算。
$7.6+0.5×0.5+4.75$
$6.7×3.2+4.3×3.2-3.2$
$7.7÷[14.5-(1.9+1.6)]$
$7.6+0.5×0.5+4.75$
$6.7×3.2+4.3×3.2-3.2$
$7.7÷[14.5-(1.9+1.6)]$
答案
12.6 32 0.7
解析
$7.6+0.5×0.5+4.75$
$=7.6+0.25+4.75$
$=7.6+(0.25+4.75)$
$=7.6+5$
$=12.6$
$6.7×3.2+4.3×3.2-3.2$
$=3.2×(6.7+4.3-1)$
$=3.2×10$
$=32$
$7.7÷[14.5-(1.9+1.6)]$
$=7.7÷[14.5-3.5]$
$=7.7÷11$
$=0.7$
$=7.6+0.25+4.75$
$=7.6+(0.25+4.75)$
$=7.6+5$
$=12.6$
$6.7×3.2+4.3×3.2-3.2$
$=3.2×(6.7+4.3-1)$
$=3.2×10$
$=32$
$7.7÷[14.5-(1.9+1.6)]$
$=7.7÷[14.5-3.5]$
$=7.7÷11$
$=0.7$
3. 计算下面各图形的面积。(横、竖每相邻两点之间的距离都是1厘米)
答案
（1）8÷2+(3-1)=6(平方厘米) （2）3÷2+(5-1)=5.5(平方厘米)
巧算:$3.14+64.8×0.537×25+5.37×6.48×75-8×64.8×0.125×53.7$。
答案
原式=3.14+6.48×5.37×25+5.37×6.48×75-8×6.48×12.5×5.37 =3.14+6.48×5.37×(25+75-8×12.5) =3.14+6.48×5.37×(100-100) =3.14+6.48×5.37×0 =3.14
解析
原式$=3.14+6.48×5.37×25+5.37×6.48×75-8×6.48×12.5×5.37$
$=3.14+6.48×5.37×(25+75-8×12.5)$
$=3.14+6.48×5.37×(100-100)$
$=3.14+6.48×5.37×0$
$=3.14$
$=3.14+6.48×5.37×(25+75-8×12.5)$
$=3.14+6.48×5.37×(100-100)$
$=3.14+6.48×5.37×0$
$=3.14$
