盈不足

1.       盈不足的历史

我国古代计算盈亏类问题的一种算术方法，借有馀﹑不足以求隐含之数。本为《周礼》九数之一。“盈不足” 算法需要给出两次假设，这是一项创造，中世纪欧洲称它为“双设法”。

2.       盈不足的概念

3.       盈不足的例题

a.       今有共买物，人出八，盈三；人出七，不足四。问人数、物价各几何？

解：设有X人。
8X-3=7X+4
8X-7X=4+3
X=7
7乘8-3=53（物价）

b.      一群人分梨，1人分1个多1个，1人分2个差2个，求多少人和多少梨？

A: 1+2/2-1=3 人 =>  4个梨。

Require Answer

6÷2(1+2)=?

To swap 2 variable values without third variable

a=a+b
b=a-b
a=a-b

a b
2 3
5 2
3

Scrolling Text in RIA Design

How to scroll Text in RIA design?

Please go to the link http://weblogs.macromedia.com/pent/archives/2007/12/scrolling_text.html

To Archive|Compress Files Then Unarchive|Decompress in MAC & PC

MAC:
invisible->chmod 711 files
archive+compress->tar -czf name.tar.gz files
unarchive+decompress->hightlight file|right click|select
BOMAchiveHelper to extract to a folder

PC:
invisible->convert batch to executable file (*.bat to *.exe)
archive+compress->Add files in WinZip to archive and compress
unarchive+decompress->highlight file|right click|select Extract to a folder

To get folder files from Server to MAC and PC

MAC:
ditto /server destination
PC:
xcopy \\server destination /S /F /D

Remove a filename from Word's recent files list

If you share a computer with several other users, then you may want to delete yours or others' filenames from Microsoft Word's (95/ 97/ 2000/ 2003) "Recent Files" list. This list records the most-recently-opened Word documents. If you've recently edited a private document and don't want it listed when the next computer user opens Word, you can remove the filename from the "Recent Files" list.

The procedure is easy. Open Microsoft Word, then hold down the Ctrl, Alt, and - keys. The pointer will turn into a subtraction sign. With this new pointer, click on the FILE menu and select the filename you want to remove from the list. Note: removing the filename from the "Recent Files" list does not delete the document from your computer.