1. 都是實(shí)數(shù)，沒(méi)有虛數(shù)
2. 10進(jìn)制，除非另外說(shuō)明。
3. billion是10的9次方，dozen是12個(gè)，π是3.14近似
4. 23.5近似到個(gè)位是24, 123.985近似到百分位是123.99,36.5近似到個(gè)位是37
5. 循環(huán)小數(shù)的循環(huán)節(jié)上畫(huà)一個(gè)橫線。
6. factor因子，可正可負(fù)，因子一般都是整數(shù)，倍數(shù)不一定
7. 最小公倍數(shù)和最大公約數(shù)
8. 余數(shù)、被除數(shù)、除數(shù)、商的定義
9. 質(zhì)數(shù)的定義
10. 奇數(shù)偶數(shù)不一定是正數(shù)
11. 0既不是正的，也不是負(fù)的
12. 小于等于、大于等于、約等于、不等于、絕對(duì)值、平方根、階乘、平行、垂直等的符號(hào)需要知道
13. 沒(méi)有定義的情況：分母為0,根號(hào)下面為負(fù)數(shù)，0的0次方
14. 有時(shí)候，字母擺在一起不表示乘法，比如consider a three-digit integer denotedby XYZ, where X, Y, and Z are digits.
15. 如果一個(gè)函數(shù)的定義域沒(méi)有明說(shuō)，那么就默認(rèn)是整個(gè)實(shí)數(shù)范圍，復(fù)合函數(shù)會(huì)考。
16. 只考?xì)W幾里德平面，三角形內(nèi)角和180
17. 直線沒(méi)有端點(diǎn)
18. 多邊形是凸的，閉合的
19. 解析幾何一般都是按照比例畫(huà)的
20. non-empty sets, empty set,intersection, union, disjoint sets or mutually exclusive sets
21. the integers from 0 to 9, inclusive。 包括了10個(gè)元素，而during the years from 1985 to 2005 不管說(shuō)不說(shuō)inclusive都包括了21年
22. measures of central tendency,measures of position, measures of dispersion
23. 如果有偶數(shù)個(gè)數(shù)，那么median表示按照升序排列的這串?dāng)?shù)字的中間兩個(gè)數(shù)的算術(shù)平均
24. mode可以不只一個(gè)
25. quartile可以指那個(gè)點(diǎn)，也可以指一個(gè)區(qū)，比如the cow’sweight is in the third quartile of the weights of the herd 這個(gè)時(shí)候quartile 就是指一個(gè)區(qū)域group
26. 25th percentile = the firstquartile; the 50th percentile equals the second quartile, or median; the 75thpercentile equals the third quartile.
27. standard deviation of the datarefers to the nonnegative square root of the mean of the squared differencesbetween m and each of the data. also known as the population standard deviationand is not to be confused with the sample standard deviation. Sample standarddeviation is divided by n-1 for technical reasons.
28. frequency distribution
29. relative frequency distributions
30. the mean of the random variable X isthe sum of the products XP(X) for all values of X.
31. the mean of a random variable X isalso called the expected value of X or the mean of the probability distributionof X
32. In any group of data, most of thedata are within about 3 standard deviations above or below the mean.
33. The process of subtracting the meanfrom each value and then dividing the result by the standard deviation iscalled standardization. It's a useful tool because for each data value, itprovides a measure of position relative to the rest of the data independentlyof the variable for which the data was collected and the units of the variable.
34. universal set
35. median 把曲線下面的面積平均分成兩塊面積相等的部分，mean要算上這塊面積的重量，所以og上那個(gè)圖的mean要在median的右邊，因?yàn)樵酵�，越�?/p>
36. 所以median是halving point, 而mean is the balance point
37. box-and-whisker plot 5個(gè)點(diǎn)L Q1 Q2 Q3 G 可以立刻看到median, interquartile range and range.
38. 正態(tài)分布：2%，14%，34%，34%，14%，2%