From 88d5d1cb097ee9ba4b28b8157b6fab439efe9a5b Mon Sep 17 00:00:00 2001 From: lucfe Date: Mon, 18 Sep 2023 15:58:28 +0800 Subject: [PATCH] 09181558 --- .../math_primary.md" | 200 +++++++ .../html css js/html.md" | 226 +++++++ .../python/python crash course.md" | 554 +++++++++++++++++- source/_posts/_plans.md | 6 + source/assets/images/html/image-4.png | Bin 0 -> 172213 bytes source/assets/images/math_primary/image-1.png | Bin 0 -> 13249 bytes source/assets/images/math_primary/image-2.png | Bin 0 -> 16944 bytes source/assets/images/math_primary/image-3.png | Bin 0 -> 27083 bytes source/assets/images/math_primary/image-4.png | Bin 0 -> 23431 bytes source/assets/images/math_primary/image-5.png | Bin 0 -> 14752 bytes source/assets/images/math_primary/image.png | Bin 0 -> 12014 bytes 11 files changed, 962 insertions(+), 24 deletions(-) create mode 100644 "source/_posts/0004 Formal science/\346\225\260\345\255\246 Mathematics/math_primary.md" create mode 100644 source/assets/images/html/image-4.png create mode 100644 source/assets/images/math_primary/image-1.png create mode 100644 source/assets/images/math_primary/image-2.png create mode 100644 source/assets/images/math_primary/image-3.png create mode 100644 source/assets/images/math_primary/image-4.png create mode 100644 source/assets/images/math_primary/image-5.png create mode 100644 source/assets/images/math_primary/image.png diff --git "a/source/_posts/0004 Formal science/\346\225\260\345\255\246 Mathematics/math_primary.md" "b/source/_posts/0004 Formal science/\346\225\260\345\255\246 Mathematics/math_primary.md" new file mode 100644 index 0000000..394a9e6 --- /dev/null +++ "b/source/_posts/0004 Formal science/\346\225\260\345\255\246 Mathematics/math_primary.md" @@ -0,0 +1,200 @@ +--- +title: math in primary school +categories: [0004 Formal science, 数学 Mathematics] +tags: [math, primary school] +--- + +## Numbers and Place Value + +### What is the difference between a ‘numeral’ and a ‘number’? + +A numeral is the symbol, or collection of symbols, that we use to represent a number. The +number is the concept represented by the numeral, and therefore consists of a whole network +of connections between symbols, pictures, language and real-life situations. + + +The same number (for example, the one we call ‘three hundred and sixty-six’) can be represented by different numerals – such as 366 in our Hindu-Arabic, place-value system, and CCCLXVI using +Roman numerals + +Because the Hindu-Arabic system of numeration is now more or less universal, the distinction between the numeral and the number is easily lost. + +### What are the cardinal and ordinal aspects of number? + +> cardinal基数； +> a number, such as 1, 2 and 3, used to show quantity rather than order +> +> ordinal序数词（如第一、第二等） +> a number that refers to the position of sth in a series, for example ‘first’, ‘second’, etc. + + +s an adjective describing a small set +of objects: two brothers, three sweets, five fingers, three blocks, and so on. This idea of a number +being a description of a set of things is called the `cardinal aspect of number`. + + +numbers used +as labels to put things in order. For example, they +turn to page 3 in a book. +The numerals and words being used here do not represent +cardinal numbers, because they are not referring to sets of three things.In these examples, ‘three’ is one thing, which is labelled three because of the +position in which it lies in some ordering process. This is called the `ordinal aspect of number`. + +The most important experience of the ordinal aspect of number is when +we represent numbers as locations on a number strip or as points on +a number line + +![Alt text](/assets/images/math_primary/image.png) + +There is a further way in which numerals are used, +sometimes called the `nominal aspect`. This is where +the numeral is used as a label or a name, without any +ordering implied. The usual example to give here +would be a number 7 bus. + +### What are natural numbers and integers? + +use for +counting: {1, 2, 3, 4, 5, 6, …}, going on forever. +These are what mathematicians choose to call the set +of `natural numbers` + +the set of `integers`: {…, –5, –4, –3, –2, –1, 0, 1, +2, 3, 4, 5, …} now going on forever in both directions. +includes both positive integers (whole numbers greater than zero) and negative integers (whole +numbers less than zero), and zero itself. + +The integer –4 is properly named ‘negative four’, + the integer +4 is named ‘positive four’, + +`natural numbers are positive integers.` + +![Alt text](/assets/images/math_primary/image-1.png) + +### What are rational and real numbers? + + include fractions and decimal +numbers (which, as we shall see, are a particular kind of(是一种特殊的) fraction), we get the set of +`rational numbers`. + +The term ‘rational’ derives from the idea that a fraction represents a ratio. + +The technical +definition of a rational number is any number that is the ratio of two integers. + +Rational numbers enable us to subdivide the +sections of the number line between the integers and to label the points in between, + +![Alt text](/assets/images/math_primary/image-2.png) + +--- + +there are other real numbers that cannot be written down as exact fractions or decimals – and are therefore not rational. + +there is no fraction or decimal that is exactly equal to the square root of 50 (written as √50). +This means there is no rational number that when multiplied by itself gives exactly the answer +50. + +– we could never get a number +that gave us 50 exactly when we squared it. + +But √50 is a real number – in the sense that it +represents a real point on a continuous number line, somewhere between 7 and 8. It represents +a real length. So this is a real length, a real number, but +it is not a rational number. It is called `an irrational number`. +利用勾股定理得到平方根数的实际长度 + +the +set of real numbers includes all rational numbers – which include integers, which in turn +include natural numbers – and all irrational numbers. + +### What is meant by ‘place value’? + +in the Hindu-Arabic system +we do not use a symbol representing a hundred to +construct three hundreds: we use a symbol representing three! Just this one symbol is needed to represent +three hundreds, and we know that it represents three +hundreds, rather than three tens or three ones, because +of the `place` in which it is written. + +in our Hindu-Arabic place-value system, all +numbers can be represented using a finite set of digits, +namely, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. + +Like most numeration systems, no doubt because of the availability of +our ten fingers for counting purposes, the system uses +ten as a base. + +Larger whole numbers than 9 are constructed using powers of the base: ten, a hundred, a +thousand, and so on. + +The place in which a digit is written, then, represents that number of one of these powers +of ten + +for example, working from right to left, in the numeral 2345 the 5 represents +5 ones (or units), the 4 represents 4 tens, the 3 represents 3 hundreds and the 2 represents +2 thousands. + +the +numeral 2345 is essentially a clever piece of shorthand, condensing a complicated mathematical +expression into four symbols, as follows: +(2 × 103) + (3 × 102) + (4 × 101) + 5 = 2345. + +Perversely, we work from right to left in determining the place values, with +increasing powers of ten as we move in this direction. But, since we read from left to right, +the numeral is read with the largest place value first + + +--- + +the principle of `exchange`. +This means that whenever you have accumulated ten in one place, this can be exchanged for +one in the next place to the left. This principle of being able to ‘exchange one of these for ten +of those’ as you move left to right along the powers of ten, or to ‘exchange ten of these for one +of those’ as you move right to left, is a very significant feature of the place-value system. + +This principle of exchanging is also fundamental to the ways we do calculations with +numbers. It is the principle of ‘carrying one’ in addition + +It also means that, +when necessary, we can exchange one in any place for ten in the next place on the right, for +example when doing subtraction by decomposition. + +It also means that, +when necessary, we can exchange one in any place for ten in the next place on the right, for +example when doing subtraction by decomposition + +### How does the number line support understanding of place value? + +![Alt text](/assets/images/math_primary/image-3.png) + +### What is meant by saying that zero is a place holder? + +‘three hundred and seven’ represented in base-ten blocks. Translated into symbols, +without the use of a zero, this would easily be confused with thirty-seven: 37. The zero is used therefore as a **place holder**; that is, to indicate the position +of the tens’ place, even though there are no tens +there: 307. It is worth noting, therefore, that when we +see a numeral such as 300, we should not think to +ourselves that the 00 means ‘hundred’.It is the position of the 3 that indicates that it stands for ‘three hundred’; the function of the zeros is to make this +position clear whilst indicating that there are no tens +and no ones. + +![Alt text](/assets/images/math_primary/image-4.png) + +### How is understanding of place value used in ordering numbers? + +It +is always the first digit in a numeral that is most significant in determining the size of the number. + +A statement that one number is greater than another (for example, 25 is greater than 16) or +less than another (for example, 16 is less than 25) is called an inequality + +### How are numbers rounded to the nearest 10 or the nearest 100? + +Rounding is an important skill in handling numbers +One skill to be learnt is to round a number or quantity to the nearest something. + +round a 2-digit number to the nearest ten. + +67 lies between 60 and 70, but is nearer to 70 + +![Alt text](/assets/images/math_primary/image-5.png) \ No newline at end of file diff --git "a/source/_posts/0004 Formal science/\350\256\241\347\256\227\346\234\272\347\247\221\345\255\246\346\212\200\346\234\257 Computer science/Software notations\302\240and\302\240tools/html css js/html.md" "b/source/_posts/0004 Formal science/\350\256\241\347\256\227\346\234\272\347\247\221\345\255\246\346\212\200\346\234\257 Computer science/Software notations\302\240and\302\240tools/html css js/html.md" index a0c4c65..feb7682 100644 --- "a/source/_posts/0004 Formal science/\350\256\241\347\256\227\346\234\272\347\247\221\345\255\246\346\212\200\346\234\257 Computer science/Software notations\302\240and\302\240tools/html css js/html.md" +++ "b/source/_posts/0004 Formal science/\350\256\241\347\256\227\346\234\272\347\247\221\345\255\246\346\212\200\346\234\257 Computer science/Software notations\302\240and\302\240tools/html css js/html.md" @@ -1,3 +1,8 @@ +--- +title: html learning +categories: [0004 Formal science, 计算机科学技术 Computer science] +tags: [html, web development] +--- ## 转义字符 HTML中<，>，&等有特殊含义（<，>，用于链接签，&用于转义），不能直接使用。这些符号是不显示在我们最终看到的网页里的，那如果我们希望在网页中显示这些符号，就要用到HTML转义字符串（Escape Sequence） @@ -483,3 +488,224 @@ The manifest file can prevent an unwieldy header full of `` and `` t ``` + +## Semantic HTML + +Semantic means "relating to meaning". Writing semantic HTML means using HTML elements to structure your content based on each element's meaning, not its appearance. + +The first code snippet uses
and , two elements with no semantic value. + +```html +
+ Three words +
+ one word + one word + one word + one word +
+
+
+
+
five words
+
+
+
three words
+
forty-six words
+
forty-four words
+
+
+
seven words +
sixty-eight words
+
forty-four words
+
+
+
+ five words +
+``` + +Let's rewrite this code with semantic elements: + +```html +
+

Three words

+ +
+
+
+

five words

+
+
+

three words

+

forty-six words

+

forty-four words

+
+
+

seven words

+

sixty-eight words

+

forty-four words

+
+
+
+

five words

+
+``` + +Semantic markup isn't just about making markup easier for developers to read; it's mostly about making markup easy for automated tools to decipher. + +### Accessibility object model (AOM) + +As the browser parses the content received, it builds the document object model (DOM) and the CSS object model (CSSOM). It then also builds an accessibility tree. Assistive devices, such as screen readers, use the AOM to parse and interpret content. The DOM is a tree of all the nodes in the document. The AOM is like a semantic version of the DOM. + +#### The role attribute +The role attribute describes the role an element has in the context of the document. The role attribute is a global attribute—meaning it is valid on all elements—defined by the ARIA specification rather than the WHATWG HTML specification, where almost everything else in this series is defined. + +### Semantic elements + +Asking yourself, "Which element best represents the function of this section of markup?" will generally result in you picking the best element for the job. The element you choose, and therefore the tags you use, should be appropriate for the content you are displaying, as tags have semantic meaning. + +## Headings and sections + +### Site `
` + +```html + + + +``` + +While the `id` and `class` attributes provide hooks for styling and JavaScript, they add no semantic value for the screen reader and (for the most part) the search engines. + +--- + +```html + +
+
Machine Learning Workshop
+ + +
+ +``` + +This at least provides semantics and enables using attribute selectors in the CSS, but it still adds comments to identify which `
` each `
` ***closes***. + +--- + +```html +
+

Machine Learning Workshop

+ +
+``` + + +This code uses two semantic landmarks: `
` and `