Start > Input a 3-digit number. >Multiply the number by 77 >Multiply the product by 13 >Result
下列有兩條問題:(a)what do you discover?(b)can you explain the dicovery(急)
更新1:
快D!!!!!!!!我要(b)既先
更新2:
正啊,聽日呢..選你啦
各位中一or二的人請進,急..暑期作業10分英皇學生
2007-08-17 10:47 pm
有一條math嘅數希望大家教我
Start > Input a 3-digit number. >Multiply the number by 77 >Multiply the product by 13 >Result
下列有兩條問題:(a)what do you discover?(b)can you explain the dicovery(急)
Start > Input a 3-digit number. >Multiply the number by 77 >Multiply the product by 13 >Result
下列有兩條問題:(a)what do you discover?(b)can you explain the dicovery(急)
回答 (2)
2007-08-17 11:03 pm
✔ 最佳答案
a) assume the 3 digit number is abc the 3 digit number become 6 digit number
ie.) abc -> abcabc
b) because multiply the product by 77 and then multiply again by 13 is equivalent to direct multiply the product by 1001
(abc *77)*13 = abc * 1001 = abcabc
2007-08-17 11:11 pm
Let 3-digit number be xxx
[(xxx) x77]x13
= (xxx) x 1001
= (xxx) x (1000+1)
= xxx000 + xxx
= xxxxxx
即將3位數再在前面多寫一次便等如答案. (其實最重要係學識分解功式)
例: 999 X77x13
= 999 x1001
= 999999
Shadow.
[(xxx) x77]x13
= (xxx) x 1001
= (xxx) x (1000+1)
= xxx000 + xxx
= xxxxxx
即將3位數再在前面多寫一次便等如答案. (其實最重要係學識分解功式)
例: 999 X77x13
= 999 x1001
= 999999
Shadow.
收錄日期: 2021-04-29 19:47:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070817000051KK02537