diff --git a/docs/Instruction/tips/register_bit.md b/docs/Instruction/tips/register_bit.md
index e6b5631fa95902eb95975fbbb225fa04047ca9be..e72489bd5c4389b4ca699f5358ca69f6fed06bbf 100644
--- a/docs/Instruction/tips/register_bit.md
+++ b/docs/Instruction/tips/register_bit.md
@@ -1,10 +1,11 @@
-# Registors
+# Registers
 
 !!! Attention
      resistor[ruh_**zi**_str] : [electrical component that implements electrical resistance](https://en.wikipedia.org/wiki/Resistor#:~:text=A%20resistor%20is%20a%20passive,transmission%20lines%2C%20among%20other%20uses.)    
      register[**reh**_juh_str] : [a memory location within the actual processor that work at very fast speeds](https://computersciencewiki.org/index.php/Registers_within_the_CPU)
 
-## Registors
+## n-ary numbers
+
 - 1 byte = 8 bits = [7:0]
 - binary
     - 2進数(0,1)
@@ -21,6 +22,22 @@
 - ref. [2進数、8進数、10進数、16進数相互変換ツール](https://hogehoge.tk/tool/number.html)
 
 
+!!! Note
+    JP   | EN        |10       |255
+    --   |---        |--       |--
+    2進数 |Binary     |0b1010   |0b11111111  
+    10進数|Decimal    |0d10　　　|0d255
+    16進数|Hexadecimal|0xA      |0xff  
+
+    1 byte = 8 bits = 2^8 = 256  
+    1B = 8b  
+
+    1**k**B = 1 [kilo] byte = 1000 B  
+    1**K**B = 1 [ke̞ː] byte = 1024 B = 2^10 B = 1KiB = 1 [kibi] byte  
+
+    1 bps = 1 [bits per second]  
+
+
 ## pinout
 ![](../images/register/ATtiny_x14.gif)