1.3/7 × 49/9 - 4/3 2.8/9 × 15/36 + 1/27 3. 12× 5/6 – 2/9 ×3 4.8× 5/4 + 1/4 5.6÷ 3/8 – 3/8 ÷6 6.4/7 × 5/9 + 3/ 7 × 5/9 7.5/2 -( 3/2 + 4/5 ) 8.7/8 + ( 1/8 + 1/9 ) 9.9 × 5/6 + 5/6 10.3/4 × 8/9 - 1/ 3 0. 12χ+ 1 .8×0.9=7.2 (9-5χ)×0.3= 1.02 6.4χ-χ=28+4.4 1 1.7 × 5/49 + 3/ 14 12.6 ×( 1/2 + 2/ 3 ) 13.8 × 4/ 5 + 8 × 1 1/5 14.3 1 × 5/6 – 5/6 15.9/7 - ( 2/7 – 10/2 1 ) 16.5/ 9 × 18 – / kloc-0/4 × 2/7 17.4/5 × 25/ 16 + 2/3 × 3/4 18. 14 × 8/7 – 5/6 × 12/ 15 19. 17/32 – 3/ 4 × 9/24 20.3 × 2/9 + 1/3 2 1.5/7 × 3/25 + 3/7 22.3/ 14 ×× 2/3 + 1/6 23. 1/5 × 2/3 + 5/6 24.9/22 + 1/ / kloc-0/ 1 ÷ 1/2 25.5/3 × 1 1/5 + 4/3 26.45 × 2/3 + 1/3 × 15 27.7/ 19 + 12/ 19 × 5/ 6 28. 1/4 + 3/4 ÷ 2/3 29.8/7 × 2 1/ 16 + 1/2 30. 10 1 × 1/5 – 1/ 5 × 2 1 3 1 .50+ 160÷40 (58+370)÷(64-45) 32. 120- 144÷ 18+35 33.347+45×2-4 160÷52 34(58+37)÷(64-9×5) 35.95÷(64-4 5) 36. / kloc-0/78- 145÷5×6+42 420+580-64×2 1÷28 37.8 12-700÷(9+3 1× 1 1) ( 136+64)×(65-345÷23) 38.85+ / kloc-0/4×(6543 8+04+208÷26) 39.(284+ 16)×(5 12-8208÷ 18) 40. 120-36×4÷ 18+35 4 1.(58+37)÷(64-9×5) 42.(6.8-6.8×0.55) ÷8.5 43.0. 12× 4.8÷0. 12×4.8 44.(3.2× 1.5+2.5)÷ 1.6 (2)3.2×( 1.5+2.5)÷ 1.6 45.6- 1 .6÷4= 5.38+7.85-5.37= 46.7.2÷0 .8- 1.2×5= 6- 1. 19×3-0.43= 47.6.5×(4.8- 1.2×4)= 0.68× 1.9+0.32× 1.9 48. / kloc-0/0. 15- 10.75×0.4-5.7 49.5.8×( 3.87-0. 13)+4.2×3.74 50.32.52-(6+9.728÷3.2)×2.5 5 1.-5+58+ 13+90+78-(-56) +50 52.-7*2-57/(3 53.(-7)* 2/( 1/3)+79/(3+6/4)54. 123+456+789+98/(-4)55.369/33-(-54-3 1/ 15.5)56.39+{ 3x[42/2x(3x8)]} 57.9 x8x 7/5x(4+6)58 But there is no answer:1.3/7× 49/9-4/32.8/9×15/36+127 3.12. 7 × 5/9 + 3/7 × 5/9 7.5/2 -( 3/2 + 4/5 ) 8.7/8 + ( 1/8 + 1/9 ) 9.9 × 5/6 + 5/6 10.3/4 × 8/9 - 1/ 3 0. 12χ+ / kloc-0/.8×0.9=7.2 (9-5χ)×0.3= 1.02 6.4χ-χ=28+4.4 1 1.7 × 5/49 + 3/ 14 12.6 ×( 1/2 + 2/ 3 ) 1 3.8 × 4/5 + 8 × 1 1/5 14.3 1 × 5/6 – 5/6 15.9/7 - ( 2/7 – 10/2 1 ) 16.5/ 9 × 1 8 – 14 × 2/7 17.4/5 × 25/ 16 + 2/3 × 3/4 18. 14 × 8/7 – 5/6 × 12/ 15 19. 17/ 32 – 3/ 4 × 9/24 20.3 × 2/9 + 1/3 2 1.5/7 × 3/25 + 3/7 22.3/ 14 ×× 2/3 + 1/6 23. 1/5 × 2/3 + 5/6 24.9/22 + / kloc-0// 1 1 ÷ 1/2 25.5/3 × 1 1/5 + 4/3 26.45 × 2/3 + 1/3 × 15 27.7/ 19 + 12/ / kloc-0/9 × 5/ 6 28. 1/4 + 3/4 ÷ 2/3 29.8/7 × 2 1/ 16 + 1/2 30. 10 1 × 1/5 – 1/ 5 × 2 / kloc-0/ 3 1.50+ 160÷40 (58+370)÷(64-45) 32. 120- 144÷ 18+35 33.347+45×2-4 160÷52 34(58+37)÷(64-9×5) 35.95÷(64-4 5) 36. 178- 145÷5×6+42 420+580-64×2 1÷28 37.8 12-700÷(9+3 1× 1 1) ( 136+64) ×(65-345÷23) 38.85+ 14×(6543 8+04+208÷26) 39.(284+ 16)×(5 12-8208÷ 18) 40. 120-36×4÷ 18+35 4 1 .(58+37)÷(64-9×5) 42.(6.8-6.8×0.55) ÷8.5 43.0. 12× 4.8÷0. 12×4.8 44.(3.2× 1.5+2.5)÷ 1.6 (2)3.2×( 1.5+2.5)÷ 1 .6 45.6- 1.6÷4= 5.38+7.85-5.37= 46.7.2÷0 .8- 1.2×5= 6- 1. 19×3-0.43= 47.6.5×(4.8- 1.2×4)= 0.68× 1.9+0.32× / kloc-0/.9 48. 10. 15- 10.75×0.4-5.7 49.5.8×( 3.87-0. 13)+4.2×3.74 50.32.52-(6+9.728÷3.2)×2.5 5 1.-5+58+ 1 3+90+78-(-56)+50 52.-7*2-57/(3 53.(-7)* 2/( 1/3)+79/(3+6/4)54. 123+456+789+98/(-4)55.369/33-(-54-3 1/ 15.5)56.39+{ 3x[42/ 2x(3x8)]} 57.9 x8x 7/5x(4+6)58a^3-2b^3+ab(2a-b)=a^3+2a^2b-2b^3-ab^2 =a^2(a+2b)-b^2(2b+a)=(a+2b)(a^2-b^2)=(a+2b)(a+b)(a-b)2。 (x^2+y^2)^2-4y(x^2+y^2)+4y^2 =(x^2+y^2-2y)^2 3。 (x^2+2x)^2+3(x^2+2x)+x^2+2x+3 =(x^2+2x)^2+4(x^2+2x)+3 =(x^2+2x+3)(x^2+2x+ 1)=(x^2+2x+3)(x+ 1)^2。 (a+ 1)(a+2)+(2a+ 1)(a-2)- 12 =a^2+3a+2+2a^2-3a-2- 12 =3a^2- 12 = 3(a+2)(a-2)5。 x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2 =[x(y+z)-y(x-z)]^2 =(xz+yz)^2 =z^2(x+y)^2 6。 3(a+2)^2+28(a+2)-20 =[3(a+2)-2][(a+2)+ 10]=(3a+4)(a+ 12)7。 (a+b)^2-(b-c)^2+a^2-c^2 =(a+b)^2-c^2+a^2-(b-c)^2 =(a+b+c)(a+b-c)+(a+b-c)(a-b+c)=(a+b-c)(a+b+c+a-b+c)= 2(a+b-c)(a+c)8。 x(x+ 1)(x^2+x- 1)-2 =(x^2+x)(x^2+x- 1)-2 =(x^2+x)^2-(x^2+x)-2 =(x^2+x-2)(x^2+x+ 1)=(x+2)(x- 1)(x^2+x+ 1) 9x^2(x- 1)^2-3(x^2-x)-56 =9x^2(x- 1)^2-3x(x- 1)-56 =[3x(x- 1)-8][3x(x- 1)+7]=(3x^2-3x-8)(3x^2-3x+7)