Numbers

1-js/05-data-types/02-number/1-sum-interface/solution.md

@@ -1,12 +1,12 @@
 
-
 ```js run demo
 let a = +prompt("The first number?", "");
 let b = +prompt("The second number?", "");
 
 alert( a + b );
 ```
 
-Note the unary plus `+` before `prompt`. It immediately converts the value to a number.
+注意在 `prompt` 之前的一元正號 `+`，它將值立刻轉換為數值。
+
+否則，`a` 和 `b` 是個字串，所以它們的加總將會是字串連接，也就是：`"1" + "2" = "12"`。
 
-Otherwise, `a` and `b` would be string their sum would be their concatenation, that is: `"1" + "2" = "12"`.

1-js/05-data-types/02-number/1-sum-interface/task.md

@@ -2,10 +2,11 @@ importance: 5
 
 ---
 
-# Sum numbers from the visitor
+# 加總由訪問者輸入的數值
 
-Create a script that prompts the visitor to enter two numbers and then shows their sum.
+建立一個腳本，提示（prompt）訪問者輸入兩個數值，然後顯示它們的總和。
 
 [demo]
 
-P.S. There is a gotcha with types.
+註：類型會有個問題。
+

1-js/05-data-types/02-number/2-why-rounded-down/solution.md

@@ -1,31 +1,30 @@
-Internally the decimal fraction `6.35` is an endless binary. As always in such cases, it is stored with a precision loss.
+在十進位分數 `6.35` 的內部是個無窮二進位，在這種情況下，它的存放會有著精度損失。
 
-Let's see:
+來看這：
 
 ```js run
 alert( 6.35.toFixed(20) ); // 6.34999999999999964473
 ```
 
-The precision loss can cause both increase and decrease of a number. In this particular case the number becomes a tiny bit less, that's why it rounded down.
+精度損失可能會導致數值的增減，在這個特殊情況下，數值變得稍微小了點，這就是為什麼它被向下進位了。
 
-And what's for `1.35`?
+而 `1.35` 呢？
 
 ```js run
 alert( 1.35.toFixed(20) ); // 1.35000000000000008882
 ```
 
-Here the precision loss made the number a little bit greater, so it rounded up.
+精度損失讓該數值稍微大了些，所以它被向上進位。
 
-**How can we fix the problem with `6.35` if we want it to be rounded the right way?**
+**若我們想要它正確的進位，該如何修正 `6.35` 的這個問題？**
 
-We should bring it closer to an integer prior to rounding:
+我們應該在進位前讓它更靠近整數：
 
 ```js run
 alert( (6.35 * 10).toFixed(20) ); // 63.50000000000000000000
 ```
 
-Note that `63.5` has no precision loss at all. That's because the decimal part `0.5` is actually `1/2`. Fractions divided by powers of `2` are exactly represented in the binary system, now we can round it:
-
+注意這個 `63.5` 完全沒有精度損失，這是因為小數部分的 `0.5` 事實上為 `1/2`。被 `2` 的次方所除的除法可以在二進位系統中被完全表示出來，現在我們可以進位它了：
 
 ```js run
 alert( Math.round(6.35 * 10) / 10); // 6.35 -> 63.5 -> 64(rounded) -> 6.4

1-js/05-data-types/02-number/2-why-rounded-down/task.md

@@ -2,21 +2,21 @@ importance: 4
 
 ---
 
-# Why 6.35.toFixed(1) == 6.3?
+# 為什麼 6.35.toFixed(1) == 6.3？
 
-According to the documentation `Math.round` and `toFixed` both round to the nearest number: `0..4` lead down while `5..9` lead up.
+根據文件 `Math.round` 和 `toFixed` 兩者皆進位到最近的數值：`0..4` 向下捨去，而 `5..9` 向上提升。
 
-For instance:
+舉個例：
 
 ```js run
 alert( 1.35.toFixed(1) ); // 1.4
 ```
 
-In the similar example below, why is `6.35` rounded to `6.3`, not `6.4`?
+跟上面類似的例子中，為什麼 `6.35` 會進位為 `6.3` 而非 `6.4`？
 
 ```js run
 alert( 6.35.toFixed(1) ); // 6.3
 ```
 
-How to round `6.35` the right way?
+要如何正確地進位到 `6.35` 呢？
 

1-js/05-data-types/02-number/3-repeat-until-number/solution.md

@@ -15,9 +15,9 @@ function readNumber() {
 alert(`Read: ${readNumber()}`);
 ```
 
-The solution is a little bit more intricate that it could be because we need to handle `null`/empty lines.
+解法較為複雜些，因為我們需要處理 `null`/空行。
 
-So we actually accept the input until it is a "regular number". Both `null` (cancel) and empty line also fit that condition, because in numeric form they are `0`.
+因此我們實際上一直接收輸入的東西，直到它是個 "正常的數值" 為止。`null`（取消）和空行這兩者也都符合此條件，因為在數值格式中它們都是 `0`。
 
-After we stopped, we need to treat `null` and empty line specially (return `null`), because converting them to a number would return `0`.
+在我們停下來之後，需要是對 `null` 和空行特別對待（return `null`），因為轉換它們為數值將會回傳 `0`。
 

1-js/05-data-types/02-number/3-repeat-until-number/task.md

@@ -2,13 +2,13 @@ importance: 5
 
 ---
 
-# Repeat until the input is a number
+# 重複動作直到輸入的是個數值為止
 
-Create a function `readNumber` which prompts for a number until the visitor enters a valid numeric value.
+建立一個函式 `readNumber` 以提示（prompt）輸入數值，直到訪問者真的輸入有效數值為止。
 
-The resulting value must be returned as a number.
+結果值必須以數值回傳。
 
-The visitor can also stop the process by entering an empty line or pressing "CANCEL". In that case, the function should return `null`.
+訪問者也可以透過輸入空行或按下 "CANCEL" 來停止程序。在這個情況下，函式應該要回傳 `null`。
 
 [demo]
 

1-js/05-data-types/02-number/4-endless-loop-error/solution.md

@@ -1,6 +1,6 @@
-That's because `i` would never equal `10`.
+這是因為 `i` 永遠不會等於 `10`。
 
-Run it to see the *real* values of `i`:
+執行這段來看看 `i` *真實* 的值：
 
 ```js run
 let i = 0;
@@ -10,8 +10,9 @@ while (i < 11) {
 }
 ```
 
-None of them is exactly `10`.
+它們之中沒有恰好為 `10` 的值。
 
-Such things happen because of the precision losses when adding fractions like `0.2`.
+這種事情發生於因為加上像是`0.2` 這樣的分數，而導致的精度損失。
+
+結論：在使用十進位小數時，避免相等性確認。
 
-Conclusion: evade equality checks when working with decimal fractions.

1-js/05-data-types/02-number/4-endless-loop-error/task.md

@@ -2,9 +2,9 @@ importance: 4
 
 ---
 
-# An occasional infinite loop
+# 偶發的無窮迴圈
 
-This loop is infinite. It never ends. Why?
+這個迴圈是無窮的，它永不停止。為什麼？
 
 ```js
 let i = 0;

1-js/05-data-types/02-number/8-random-min-max/solution.md

@@ -1,11 +1,11 @@
-We need to "map" all values from the interval 0..1 into values from `min` to `max`.
+我們需要 "對應" 0..1 區間內的所有值至 `min` 到 `max` 之間的值上。
 
-That can be done in two stages:
+可在兩步驟內完成：
 
-1. If we multiply a random number from 0..1 by `max-min`, then the interval of possible values increases `0..1` to `0..max-min`.
-2. Now if we add `min`, the possible interval becomes from `min` to `max`.
+1. 若我們對 `max-min` 乘上一個在 0..1 之間的隨機數，則可能值的區間會由 `0..1` 增加至 `0..max-min`。 
+2. 現在若我們加上 `min`，則區間將變成 `min` 至 `max`。
 
-The function:
+該函式：
 
 ```js run
 function random(min, max) {

1-js/05-data-types/02-number/8-random-min-max/task.md

@@ -2,16 +2,17 @@ importance: 2
 
 ---
 
-# A random number from min to max
+# 由 min 至 max 的隨機數
 
-The built-in function `Math.random()` creates a random value from `0` to `1` (not including `1`).
+內建函式 `Math.random()` 建立一個從 `0` 到 `1` 的隨機值（不包括 `1`）。
 
-Write the function `random(min, max)` to generate a random floating-point number from `min` to `max` (not including `max`).
+寫個函式 `random(min, max)` 在 `min` 至 `max` 中產生隨機的浮點數（不包括 `max`）。
 
-Examples of its work:
+可行的範例：
 
 ```js
 alert( random(1, 5) ); // 1.2345623452
 alert( random(1, 5) ); // 3.7894332423
 alert( random(1, 5) ); // 4.3435234525
 ```
+

1-js/05-data-types/02-number/9-random-int-min-max/solution.md

@@ -1,6 +1,6 @@
-# The simple but wrong solution
+# 簡單但錯誤的解法
 
-The simplest, but wrong solution would be to generate a value from `min` to `max` and round it:
+最簡單卻錯誤的解法，是產生由 `min` 至 `max` 的值，再進位它：
 
 ```js run
 function randomInteger(min, max) {
@@ -11,28 +11,28 @@ function randomInteger(min, max) {
 alert( randomInteger(1, 3) );
 ```
 
-The function works, but it is incorrect. The probability to get edge values `min` and `max` is two times less than any other.
+這個函式可以運行，但它不正確。得到邊緣值 `min` 和 `max` 的機率比其它值還要少了兩倍。
 
-If you run the example above many times, you would easily see that `2` appears the most often.
+若你執行上述範例許多次，你將會很容易就看到 `2` 較常出現。
 
-That happens because `Math.round()` gets random numbers from the interval `1..3` and rounds them as follows:
+那是因為 `Math.round()` 由區間 `1..3` 之間得到隨機數，並像下面這樣進位：
 
 ```js no-beautify
 values from 1    ... to 1.4999999999  become 1
 values from 1.5  ... to 2.4999999999  become 2
 values from 2.5  ... to 2.9999999999  become 3
 ```
 
-Now we can clearly see that `1` gets twice less values than `2`. And the same with `3`.
+現在我們可以清楚看到 `1` 比 `2` 還少了兩倍，且同樣情況對 `3` 也是。
 
-# The correct solution
+# 正確的解法
 
-There are many correct solutions to the task. One of them is to adjust interval borders. To ensure the same intervals, we can generate values from `0.5 to 3.5`, thus adding the required probabilities to the edges:
+對此課題有許多正確的解法，其中一種是調整區間邊界。要保證同樣的區間，我們可以從 `0.5 至 3.5` 之間來生成值，故此可讓邊緣加上所需要的機率：
 
 ```js run
 *!*
 function randomInteger(min, max) {
-  // now rand is from  (min-0.5) to (max+0.5)
+  // 現在 隨機值從（min-0.5）到（max+0.5）
   let rand = min - 0.5 + Math.random() * (max - min + 1);
   return Math.round(rand);
 }
@@ -41,12 +41,12 @@ function randomInteger(min, max) {
 alert( randomInteger(1, 3) );
 ```
 
-An alternative way could be to use `Math.floor` for a random number from `min` to `max+1`:
+另一個替代的做法是對於 `min` 與 `max+1` 之間的隨機數使用 `Math.floor`：
 
 ```js run
 *!*
 function randomInteger(min, max) {
-  // here rand is from min to (max+1)
+  // 這邊的隨機值由 min 到（max+1）
   let rand = min + Math.random() * (max + 1 - min);
   return Math.floor(rand);
 }
@@ -55,12 +55,13 @@ function randomInteger(min, max) {
 alert( randomInteger(1, 3) );
 ```
 
-Now all intervals are mapped this way:
+現在所有區間以這樣的方式被對應：
 
 ```js no-beautify
 values from 1  ... to 1.9999999999  become 1
 values from 2  ... to 2.9999999999  become 2
 values from 3  ... to 3.9999999999  become 3
 ```
 
-All intervals have the same length, making the final distribution uniform.
+所有區間有著同樣的長度，使得最後結果是均勻分佈的。
+

1-js/05-data-types/02-number/9-random-int-min-max/task.md

@@ -2,19 +2,19 @@ importance: 2
 
 ---
 
-# A random integer from min to max
+# 由 min 至 max 的隨機整數
 
-Create a function `randomInteger(min, max)` that generates a random *integer* number from `min` to `max` including both `min` and `max` as possible values.
+建立一個函式 `randomInteger(min, max)` 來生成一個從 `min` 至 `max` 的隨機 *整數*，包含 `min` 與 `max` 兩者皆為可能的值。
 
-Any number from the interval `min..max` must appear with the same probability.
+任何在 `min..max` 區間的數值必須以相同的機率出現。
 
-
-Examples of its work:
+可行的範例：
 
 ```js
 alert( randomInteger(1, 5) ); // 1
 alert( randomInteger(1, 5) ); // 3
 alert( randomInteger(1, 5) ); // 5
 ```
 
-You can use the solution of the [previous task](info:task/random-min-max) as the base.
+你可以使用 [前一個課題](info:task/random-min-max) 的解答作為基礎來思考。
+