Math topic中文

Letters represent numbers

using letters to represent numbers

Practice questions

  1. 1Containers X and Y are rectangular containers. The base area of Container X is 30 cm^2 and the base area of Container Y…
  2. 2Andy had $5x. After buying apples at 60c each, he had $2x left. How many apples did Andy buy? Answer: ___
  3. 3n is a positive integer. Explain whether, for all n, (7n+2)2−(7n−1)2(7n+2)^{2}-(7n-1)^{2} is a multiple of 3. Answer ___
  4. 4A bag contains 4 black coins, 7 red coins and 11 white coins. Two coins are drawn from the bag at random, one after anot…
  5. 5给出下列判断：①单项式−12px2-\dfrac{1}{2}px^{2}的系数为−12-\dfrac{1}{2}；②整式x−2xy+1x-2xy+1是二次三项式；③多项式3x2y3−px5+12y3x^{2}y^{3}-px^{5}+\dfrac{1}{2}y的次数…
  6. 6A group of singers are arranged in 5 rows. There are 7 singers in the second row. Each row has nn more singers than the…
  7. 7Thomas and Siti had cookies in the ratio 3 : 7. After Thomas bought another 42 cookies and Siti ate 18 cookies of her ow…
  8. 8y is inversely proportional to the square of x, x>0x > 0. If x is increased by 25%, find the percentage change in y. Answ…
  9. 9By completing the square or otherwise, express xx in terms of yy given that y=x2−4x+6y = x^2 - 4x + 6. Answer x = ___ or ___…
  10. 10一本漫画书，已经看了10天，每天看x页，一共看了 （ ___ ） 页。
  11. 11Simplify 20r+5r+7−r20r + 5r + 7 - r. Ans: ___
  12. 12一艘轮船在静水中的速度为aa千米//小时，水流的速度为1010千米//小时，轮船顺水航行33小时的航程与逆水航行22小时的航程相差 ___ 千米((用含aa的式子表示).).
  13. 13Adam has some 50-cent and 20-cent coins in his wallet. Given that he has a total of 73 coins adding up to a value of $2…
  14. 14已知△ABC\triangle ABC中，∠B∠B是∠A∠A的22倍，∠C∠C比∠A∠A大20∘20^{\circ}，则∠A∠A等于()() A. 40∘40^{\circ} B. 60∘60^{\circ}…
  15. 15Omar spent $162 more than 1/7 of his monthly salary on transport. He spent $40 less than 1/6 of his remaining salary o…
  16. 16某种储蓄的月利率是0.8%，存入100元本金后，本息之和用所存月数x表示的式子为 元．
  17. 17若关于xx、yy的多项式x2−2kxy+y2+6xy−6x^{2}-2kxy+y^{2}+6xy-6中不含xyxy项，则k=k=___.
  18. 18请写出一个系数为负数，次数为22的单项式，这个单项式可以为 ___.
  19. 19按一定规律排列的单项式：−4a2-4a^{2}，9a49a^{4}，−16a6-16a^{6}，25a825a^{8}，−36a10-36a^{10}，49a1249a^{12}，…，第nn个单项式是()(\quad) A. (−1)nn2a2n(-1)^{n}n^{2}a^{2n}…
  20. 20Elva invested a sum of money in an account paying compound interest at 4% per year. After 3 years, there was $89 989.12…
  21. 21A bag contains 12 balls. 2 of the balls are red, n are green balls and the rest are blue balls. Eunice takes two balls f…
  22. 22我校“阳光体育运动”已经正式启动，学校准备为同学们购买跳绳120根，若每条跳绳x元． （1）学校拿去1000元，应找回多少元？（用含有字母的式子表示出来） （2）若x＝7，计算一下应找回多少元？
  23. 23某村原有林地108公顷，旱地54公顷，为保护环境，需把一部分旱地改造为林地，使旱地面积占林地面积的20%．设把x公顷旱地改为林地，则可列方程（ ） A. 54﹣x=20%×108 B. 54﹣x=20%（108+x） C. 54+x=20%…
  24. 24甲数是n，比乙数的3倍少3，则乙数是（ ） A. 3n-3 B. （n+3）÷3 C. （n-3）÷3
  25. 25The approximate mass of the earth is 5.976×10245.976 \times 10^{24} kg. How many times is the earth heavier than an average male…
  26. 26Shamil paid $22xx for 1 table and 3 chairs. The price of 1 chair was 25\frac{2}{5} of the price of the table. How much…
  27. 27Rectangle ACDF shown below is made up of a square and a rectangle. The perimeter of rectangle ACDF is (2y+15) cm(2y + 15)\text{ cm}…
  28. 28The average mass of Bags W and X is 25 kg. The average mass of Bag X and Bag Y is 30 kg. The average mass of Bag Y and B…
  29. 29A chess club currently has 37 male members and 16 female members. The club hosted a Valentine's Day event to attract mar…
  30. 30某生产车间有6060名工人生产太阳镜，11名工人每天可生产镜片200200片或镜架5050个.应如何分配工人生产镜片和镜架，才能使每天生产的产品配套？
  31. 31一个长方形长为70厘米，剪去一个最大的正方形后，剩下的是一个小长方形，则这个小长方形周长是 厘米．
  32. 32Diagram 1 shows an equilateral triangle with sides of length 1 unit. An inverted white equilateral triangle with sides o…
  33. 33A container of juice can fill either 35 bottles or 55 cups exactly. The capacity of each bottle is 60 ml more than each…
  34. 34我市某校为了创建书香校园，去年购进一批图书.经了解，科普书的单价比文学书的单价多44元，用1200012000元购进的科普书与用80008000元购进的文学书本数相等． (1)文学书和科普书的单价各多少钱？ (2)今年文学书和科普书的单…
  35. 35Find the value of yy in 50+5y=11050 + 5y = 110.
  36. 36Six identical rectangular boxes can be stored in a cupboard 1.5 m high. Two arrangements are shown below. The arrangemen…
  37. 37In a class of 36 students, each student is either in a sports team or a performing arts club. Each student is also eithe…
  38. 38The figure below is made up of a rectangle and a square. The ratio of the area of the rectangle to the area of the squar…
  39. 39哥哥存的零花钱比妹妹的2倍少20元，比弟弟的2倍多10元，弟弟和妹妹谁存的零花钱多？多多少？
  40. 40某影碟出租店开设两种租碟方式：一种是零星租碟，每张收费11元；另一种是会员卡租碟，会员每月交会员费1212元，租碟费每张0.40.4元.小彬经常来该店租碟，若小彬每月租碟数量为xx张． (1)分别写出两种租碟方式下小彬应付…
  41. 41The figure below is made up of a square and 4 semicircles. The perimeter of the figure is 20π20\pi cm. What is the perime…
  42. 42Fatimah had some two-dollar and five-dollar notes in her money box. She had 3 fewer two-dollar notes than five-dollar no…
  43. 43Uncle John sold (p+4)(p + 4) muffins on Monday. He sold 2p2p more muffins on Tuesday than on Monday. Altogether, he sold 24…
  44. 44将若干个苹果分给孩子若干人，若每人5个，则不足2个，若每人4个则尚余3个，设孩子有x人，可列出方程 ．
  45. 45把10个苹果分成三堆，要求每堆至少1个，至多5个，则不同的分法共有（ ） A. 4种 B. 5种 C. 6种 D. 7种
  46. 46用代数式表示“2m与5的差”为（ ） A. 2m－5 B. 5－2m C. 2(m－5) D. 2(5－m)
  47. 47Complete the table of values for y=x−4x2y = x - \frac{4}{x^2}. Values are given to one decimal place where appropriate. Compl…
  48. 48某班科技兴趣小组的学生，将自己的作品向本组其他成员各赠送一件，全组共相互赠送作品56件，若全组有x名同学，则根据题意列出的方程是（ ） A. x（x-1）=56×2 B. 2x（x+1）=56 C. x（x+1）=56 D. x（x-1）=…
  49. 49A factory prints posters for corporate events. The prices of printing posters of different sizes are listed below. The f…
  50. 50王先生到银行存了一笔三年期的定期存款，年利率是4.25%.4.25\%.若到期后取出得到本息((本金++利息)33825)33825元.设王先生存入的本金为xx元，则下面所列方程正确的是()() A. x+3×4.25%x=33825x+3×4.25\%x=33825…
  51. 51铅笔每枝a元，买了m枝，付出b元，应找回 元．
  52. 52小明和爸爸一起植树，爸爸每小时植树10棵，植了一段时间后小明接着植，小明每小时植6棵，两人共植树8小时，共植了60棵。问：小明植了多少棵？
  53. 53En En packed all 732 cookies into a mixture of large and small boxes. He filled each large box with 30 cookies and each…
  54. 54In the figure, ABC and DEF are right-angled triangles. The base of triangle DEF is twice as long as the base of triangle…
  55. 55Simplify the following expression. 7m+5−3m−47m + 5 - 3m - 4 Ans: ___
  56. 56Mr Tan designed two computer models X and Y. Both have the same manufacturing cost. Mr Tan engaged his existing client M…
  57. 57The figure shown is made up of rectangle ABCD, a circle with FG as the diameter, 2 identical small semi-circles with dia…
  58. 58Susan had 117 beads and marbles altogether. The beads and marbles were either white or black. 20%20\% of the beads and 50%50\%…
  59. 59勾股定理最早出现在商高的《周髀算经》：“勾广三，股修四，经隅五”．观察下列勾股数：33，44，55；55，1212，1313；77，2424，2525；…，这类勾股数的特点是：勾为奇数，弦与股相…
  60. 60The table below shows numbers from 1 to 56. Kai and Ray are given a plastic frame that covers exactly 9 squares of the t…