Factors

A number may be made by multiplying two or more other numbers together. The numbers that are multiplied together are called factors of the final number. All numbers have a factor of one since one multiplied by any number equals that number. All numbers can be divided by themselves to produce the number one. Therefore, we normally ignore one and the number itself as useful factors.

The number fifteen can be divided into two factors which are three and five.

The number twelve could be divided into two factors which are 6 and 2. Six could be divided into two further factors of 2 and 3. Therefore the factors of twelve are 2, 2, and 3.

If twelve was first divided into the factors 3 and 4, the four could be divided into factors of 2 and 2. Therefore the factors of twelve are still 2, 2, and 3.

There are several clues to help determine factors.

·     Any even number has a factor of two

·     Any number ending in 5 has a factor of five

·     Any number above 0 that ends with 0 (such as 10, 30, 1200) has factors of two and five.

To determine factors see if one of the above rules apply (ends in 5, 0 or an even number). If none of the rules apply, there still may be factors of 3 or 7 or some other number.

因素

一個數字可以由兩個或更多其他數相乘在一起。相乘的數字被稱為最終數目的因素。所有數值都有一個的一個因素，因為任何數目乘以等於該號碼。所有的數字可以分為由自己來生產的頭號。因此，我們通常忽略了一個和自己有用的因素。

的數目15可分為兩個因素是三個和五個。

可分為兩個因素是6和2的數目12。六個可分為2和3的兩個另外的因素。因此，十二的因素是2，2，和3。

如果12首先被分成的因素3和4，四個可分為2和2個因素。因此十二的因素仍然是2，2，和3。

有幾個線索，以幫助確定因素。

·     任何偶數有兩個因素

·     尾數為5的任何數，有五個因素

·     0以上的任意數量的結束用0（如10，30，1200）的2和5的因素。

要確定因素看到如果上述規則之一的適用於（結束5星，0或偶數）。如果沒有適用的規則，還有可能是3或7或其他數字的因素。