七年级下计算题专项练习120题

七年级下计算题专项练习120题一、实数的运算实数运算作为代数的入门，是我们后续学习更复杂运算的基础。请同学们注意运算顺序，以及符号的变化，尤其是平方根和立方根的性质。（一）平方根与立方根的计算1.√4+√9-√162.∛8+∛(-27)+√13.√25×√(1/25)-√04.∛64÷∛(-8)+√365.√(16/25)+∛(-1/8)6.√121-√144+∛10007.∛(-1)-√0.01+√(1/4)8.√(0.36)×∛(1-7/8)9.√(49/121)÷∛(27/64)10.√(1+9/16)+∛(-1/64)（二）实数的加减乘除混合运算11.3√2+5√2-2√212.√3×√6÷√213.(√5+2)(√5-2)14.(3√2-√3)²15.2√12+3√48-√7516.√(1/3)+√27-√1217.(√20-√5)÷√518.√8×√(1/2)-√3×√319.(√3+√2)²-(√3-√2)²20.(√18-√8)×√2二、整式的运算整式的运算包括幂的运算、整式的加减乘除以及乘法公式的应用，这部分内容需要同学们熟练掌握各种运算法则，并能灵活运用。（一）幂的运算21.a³·a⁵22.(b²)⁴23.(2c)³24.d⁶÷d²(d≠0)25.(e³)²·e⁴26.(f⁴)⁵÷f¹⁰27.(3g²h³)²28.(h²)³·(h³)²29.(2k³)⁴÷(k²)³30.(mⁿ)²·(m²)ⁿ（二）整式的加减31.(3x²+2x-1)+(2x²-x+5)32.(5a²b-3ab²)-(2a²b+4ab²)33.3(2y²-3y+1)-2(4y²-y-5)34.(x³-2x²+x-1)-(x³-x²+2x+3)35.先化简，再求值：(2a²b+ab²)-2(a²b-1)-2ab²-2，其中a=2,b=-1（三）整式的乘除36.2x·(3x²-4x+5)37.(-3a²b)·(2ab²-ab)38.(x+2)(x+3)39.(2y-1)(3y+4)40.(m-3n)(m+5n)41.(4x³y²)÷(2x²y)42.(-12a⁴b³c)÷(3a²b)43.(6p⁴q⁵-9p³q⁴)÷(3p²q³)44.(x³-2x²+x)÷x45.(a⁴b⁷-0.5a³b⁸+2a²b⁶)÷(-0.5a²b⁶)（四）乘法公式的应用46.(x+5)²47.(2y-3)²48.(3m+n)(3m-n)49.(a-2b)²50.(x²+y³)(x²-y³)51.(2p+3q)(-2p+3q)52.(1/2a+4b)²53.(x-y-z)²(提示：可将(x-y)看作一个整体)54.(a+b+c)(a+b-c)55.(m+2n)³(提示：(m+2n)(m+2n)²，再用完全平方公式)三、分式的运算分式运算的关键在于理解分式的基本性质，掌握约分、通分的技巧，并注意运算过程中的符号变化以及分母不为零的条件。（一）分式的化简（约分）56.(6x²y³)/(8xy⁴)57.(a²-b²)/(a+b)58.(m²-4m+4)/(m²-4)59.(x³-4x)/(x²-4x+4)60.(y²+y-2)/(y²-1)（二）分式的乘除61.(a/b)·(b/c)62.(x²/y³)÷(x/y²)63.(3m/2n)·(4n²/9m³)64.(a²-9)/(a²+6a+9)÷(a-3)/(a+3)65.(x²-4y²)/(x²+4xy+4y²)·(x+2y)/(x-2y)（三）分式的加减66.1/a+2/a67.3/b-5/b68.1/x+1/y69.a/(a-b)+b/(b-a)70.1/(x+1)+1/(x-1)71.(x)/(x²-9)-3/(x²-9)72.2/(m²-m)+1/(m-1)73.(1/(a+1))-(a/(a²-1))74.(x/(x-2))-(x/(x+2))75.(1/(y+3))+(6/(y²-9))四、方程组的求解解方程组是代数中的重要技能，包括代入消元法和加减消元法。请同学们熟练掌握这两种方法，并能根据方程组的特点选择合适的解法。（一）解二元一次方程组76.{x+y=5{x-y=177.{2a+b=7{a-2b=178.{3m-2n=5{4m+n=1479.{5x+2y=8{3x-4y=1480.{(x/2)+(y/3)=2{2x+3y=2481.{x+y=300{5%x+53%y=300×25%82.{3(x+1)=y-5{5(y+1)=3(x-5)83.{(m/3)-(n/4)=1{(m/2)+(n/3)=284.{2x+y=3{3x-5y=1185.{0.2x+0.3y=1.2{0.5x-0.7y=0.1（二）解三元一次方程组86.{x+y+z=6{x+y-z=2{x-y+z=487.{a+b=3{b+c=4{c+a=588.{2x-y+z=3{3x+4y-z=8{x-5y+2z=-1五、不等式（组）的求解解一元一次不等式（组）是利用不等式的基本性质，将不等式逐步变形，求出未知数的取值范围。注意在系数化为1时，若系数为负，不等号方向要改变。（一）解一元一次不等式89.2x-1>590.3x+2≤8-x91.(y-1)/2<(2y+1)/392.1-(x-1)/3≥(2x+3)/293.5(x-1)<3x+194.(3m)/4-1≤(m+2)/395.2(n+1)-3(n-1)>096.(x+5)/2-1<(3x+2)/297.-3(2p+5)>2(p-1)98.(q-1)/5+1≥(q+4)/2（二）解一元一次不等式组99.{x+1>0{2x-1<3100.{3x-2≥1{4x-5<3101.{2y-1>y+1{y+8<4y-1102.{(z-1)/2≤1{1-2(z-2)<3103.{3a-2<a+2{8-a≥1-3(a-1)104.{5x-1>3(x+1){(x-2)/2≤7-(3x)/2105.{(2m-1)/3-(5m+1)/2≤1{5m-1<3(m+1)106.{1-(x-1)≥0{(x+1)/2-(x-1)/3<1107.{3(x-2)+4<5x{(x-1)/2-x≥3x+1108.{(y+1)/3-(y-1)/2≥(y-1)/6{2(y-1)+3>5y（三）不等式的简单应用（根据解集求参数范围）109.若关于x的不等式2x-m≤0的正整数解是1,2,3，求m的取值范围。110.若不等式组{x>a{x<3无解，求a的取值范围。参考答案（以下为各题的简要答案或提示，详细解题过程需要同学们自行完成哦！）1.12.-23.14.-25.0.36.97.-0.18.0.39.4/310.1.2511.6√212.313.114.21-6√615.15√316.(4√3)/317.118.-119.8√620.221.a⁸22.b⁸23.8c³24.d⁴25.e¹⁰26.f¹⁰27.9g⁴h⁶28.h¹²29.16k⁶30.m⁴ⁿ31.5x²+x+432.3a²b-7ab²33.-2y²-7y+1334.-x²-x-435.-2(提示：化简后为-2)36.6x³-8x²+10x37.-6a³b³+3a³b²38.x²+5x+639.6y²+5y-440.m²+2mn-15n²41.2xy42.-4a²b²c43.2p²q²-3pq44.x²-2x+145.-2a²b+ab²-446.x²+10x+2547.4y²-12y+948.9m²-n²49.a²-4ab+4b²50.x⁴-y⁶51.9q²-4p²52.0.25a²+4ab+16b²53.x²+y²+z²-2xy+2yz-2xz54.a²+2ab+b²-c²55.m³+6m²n+12mn²+8n³56.3x/(4y)57.a-b58.(m-2)/(m+2)59.x(x+2)/(x-2)60.(y+2)/(y+1)61.a/c62.x/y63.2n/(3m²)64.165.166.3/a67.-2/b68.(y+x)/(xy)69.170.2x/(x²-1)71.1/(x+3)72.3/m73.-1/(a-1)74.4x/(x²-4)75.1/(y-3)76.{x=3,y=2}77.{a=3,b=1}78.{m=3,n=2}79.{x=2,y=-1}80.{x=0,y=8}81.{x=200,y=100}82.{x=-5,y=-7}83.{m=4,n