What is the difference between 差不多，几乎，差点? Kindly explain in simple words with examples.

Question

Answer

●●●差不多= ① almost, nearly (not completely).
              ② just so-so,  passable (fairly good but not excellent satisfactory.)
              
例如:  
我差不多到山顶了。
(I am almost at the top of the mountain.)
他差不多爬到山顶了.
( He almost/nearly climbed the top of the mountain.)
我的数学差不多。
(My math is just so-so.)
他的歌唱的差不多.
(  His singing is almost passable.)

●●●几乎= almost, nearly (not completely)

例如：

我几乎到山顶了。
(I am almost at the top of the mountain.)
他几乎爬到山顶了.
( He almost/nearly climbed the top of the mountain.)

●●● 差点= ①  almost, nearly (not completely).
                      ② lower than your usual ability, situation level and degree， a bit weak/poor.

例如：
我差点到山顶了。
(I am almost at the top of the mountain.)
他差点爬到山顶了.
( He almost/nearly climbed the top of the mountain.)
 他的身体差点。
(His health is a bit poor.）
你发挥的能力差点。
Your ability to perform is a bit weak.

另外还要注意: 
■有一点差(lower than your usual ability, situation level and degree， a bit weak/poor.) 
■差一点（almost）(=几乎)
■ 差多了（much worse） (  例如， 你的数学差多了→Your mathematics is much worse.
。
■ 差…不到…。（例如 ，差7天不到一年 (seven days short of a year)

不差= very good/ nice 
(这女孩长得不差, 你的话说的不差。)