虚实篇 NO.4：

故形人而我无形，则我专而敌分。

我专为一，敌分为十，是以十攻其一也。

则我众敌寡，能以众击寡者，则吾之所与战者约矣。

吾所与战之地不可知，不可知则敌所备者多，敌所备者多，则吾所与战者寡矣。

故备前则后寡，备后则前寡，备左则右寡，备右则左寡，无所不备，则无所不寡。

寡者，备人者也；众者，使人备己者也。

这句啥意思：

所以，使敌军处于暴露状态而我军处于隐蔽状态，这样我军兵力就可以集中而敌军兵力就不得不分散。

（如果敌我总兵力相当），我集中兵力与一点，而敌人分散为十处，我就是以十对一。

这样，（在局部战场上）就出现我众敌寡的态势，在这种态势下，则我军所与战者用力少而成功多也。

敌军不知道我军所预定的战场在哪里，就会处处分兵防备，防备的地方越多，能够与我军在特定的地点直接交战的敌军就越少。
所以防备前面，则后面兵力不足，防备后面，则前面兵力不足，防备左方，则右方兵力不足，防备右方，则左方兵力不足，所有的地方都防备，则所有的地方都兵力不足。

兵力不足，全是因为分兵防御敌人；兵力充足，是由于迫使敌人分兵防御我。
英文这么说：

By discovering the enemy's dispositions and remaining invisible ourselves, we can keep our forces concentrated,while the enemy's must be divided.
We can form a single united body, while the enemy must split up into fractions. Hence there will be a whole pitted against separate parts of a whole,which means that we shall be many to the enemy's few.
And if we are able thus to attack an inferior force with a superior one, our opponents will be in dire straits.
The spot where we intend to fight must not be made known; for then the enemy will have to prepare against a possible attack at several different points;and his forces being thus distributed in many directions,the numbers we shall have to face at any given point will be proportionately few.
For should the enemy strengthen his van,he will weaken his rear; should he strengthen his rear,he will weaken his van; should he strengthen his left,he will weaken his right; should he strengthen his right,
he will weaken his left. If he sends reinforcements everywhere,he will everywhere be weak.
Numerical weakness comes from having to prepare against possible attacks; numerical strength, from compelling our adversary to make these preparations against us.

《敌众我寡怎么办》

第一：集中优势兵力各个击破
第二：突袭敌军要害，如粮草、后勤、司令部指挥所等，使敌陷入群龙无首或是有兵不能用、涣散军心的境地。
第三：使用计谋扭转局势，比如出奇兵奇袭、拒险作战、兵分两路头尾夹击等，根据具体的作战情况制定有效的方案，因为在战场上作战人数的多少不是绝对的决定性因素，机谋、战略、士气、装备、地理等都不同程度上的占有一定影响。简要的说，只要扬长避短，发挥己方优势，对敌方弱势进行打击，同时避免己方的不利因素的影响，这样就往往能够胜利。