假設目標是數到\(n\)就贏
首先算出\(n\)除以 的餘數
一開始就先拿那麼多個
接下來每回合如果別人拿\(x\)個,我就拿 個
\(4\)
\(4-x\)
如果\(n\)除以\(4\)的餘數是\(0\)怎麼辦?
如果每個人變成可以數1~4個數字怎麼辦?
有12顆蘋果,可以平均分給多少人?
\(12=1 \times 12 = 2\times 6 = 3\times 4\)
12有6個因數
只有兩個因數的數
難以平分的蘋果
1,2,3,4,5
2,3,5,7,11,13,15,17
\(12 = 2 \times 2 \times 3\)
練習遊戲:wallprime
pencil
school bag
Computer
隨便說出兩個用來打招呼的句子!
兩個人輪流數數-目標數到50!
(1)數到有2的數字或是2的倍數要用拍手代替
(2)數到有7的數字或是7的倍數要用拍手代替
請對24做質因數分解
\(2\times 2\) 可以整除 \(3 \times 3 \times 5 \times 7\)嗎?
\(3\times 7\) 可以整除 \(3 \times 3 \times 5 \times 7\)嗎?
\(3\times 5 \times 5\) 可以整除 \(3 \times 3 \times 5 \times 7\)嗎?
school bag
年齡
age
eraser
一年級
二年級
兩個數字共同的因數,稱為公因數
像1,2就是6跟8的公因數
兩個數字共同的倍數,稱為公倍數
像12,24,36,...就是6跟4的公倍數
兩個數字共同的因數中最大的,稱為最大公因數
像2就是6跟8的最大公因數
兩個數字共同的倍數中最小的,稱為最小公倍數
像12就是6跟4的最小公倍數
2跟10 | 18跟12 | |
最大公因數 | ||
最小公倍數 |
2
10
6
36
\(18 = 2 \times 3 \times 3\)
\(12 = 2 \times 2 \times 3\)
最大公因數\(= 2 \times 3\)
最小公倍數\(= 2 \times 2 \times 3 \times 3\)
16跟10的最小公倍數、最大公因數?
1. 錢薇娟為甚麼會想打籃球?
2. 錢薇娟做了哪些努力?
book
ruler
computer
20的因數:
1
2
4
5
10
20
16的因數:
1
2
4
8
16
20跟16的公因數:
1
2
4
20跟16的最大公因數:
4
train
picture
cake
plane
elephant
pencil
picture
10的倍數:
10
20
30
40
50
60
16的倍數:
16
32
48
64
80
10跟16的公倍數:
80
160
240
10跟16的最小公倍數:
80
70
80
90
100
96
112
3
3
4
4
4
2
5
3
3
3
clown
yo-yo
puzzle
What do you have?
I have a doll, a robot, and a yo-yo.
動動腦
多久之後,所有草地都會被水淹到?
\(1,2,4,8,16,\)
\(1,2,4,8,16,\)
\(7122\)?
\(32\)?
\(1,2,4,8,16,7122\)
\(1,2,4,8,16,32\)
k = 1
for i in range(5):
print(k)
k *= 2
k = 1
for i in range(4):
print(k)
k *= 2
print(7122)
A = [1,2,4,8,16,7122]
for i in range(5):
print(A[i])
\(C(x) = \min\{l(p):p \text{ is an encoding/program of }x\}\)
Think of \(x,p\) as binary strings(or natural numbers).
\(C(x) = \min\{l(p):p \text{ is an encoding/program of }x\}\)
Think of \(x,p\) as binary strings(or natural numbers).
A more formal definition
\(C_f(x) = \min\{l(p):f(p) = x\}\)
Where \(f\) is some (partial) function.
\(C(x) = \min\{l(p):p \text{ is an encoding/program of }x\}\)
Think of \(x,p\) as binary strings(or natural numbers).
A more formal definition
\(C_f(x) = \min\{l(p):f(p) = x\}\)
Where \(f\) is some (partial) function.
How should we choose \(f\)? (C++, python, Eric Xiao, ...?)
Maybe \(f\) should be the "minimal" (additively optimal) function:
\(\forall g,x, C_f(x) \leq C_g(x) + c_g\)
Such \(f\) doesn't exist:
Let \(g(i) = x_i\), where \(C_f(x_i) \geq i\)
Maybe \(f\) should be the "minimal" (additively optimal) function:
\(\forall g,x, C_f(x) \leq C_g(x) + c_g\)
Perhaps we should not consider all functions.