➤Decimal ⇢ 10 Unique digit ⟶ 0,1,2,3,4,5,6,7,8,9

 ➤Binary ⇢ 2 Unique digit ⟶ 0,1

 ➤Octal ⇢ 8 Unique digit ⟶ 0,1,2,3,4,5,6,7

 ➤Hexadecimal ⇢ 16 Unique digit ⟶ 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

Where,
A = 10,
B = 11,
C = 12,
D = 13,
E = 14, &
F = 15


⧪ Conversion from decimal to Binary

 (a) (30)₁₀ = (...)₂  



Note :
 If we have to convert any decimal to others then divide that decimal with the desired number. like in above we have to convert DECIMAL to BINARY{means base 2}. so we divide that decimal with 2 and we store REMAINDER in a manner way, after finishing the division simply we have to write REMAINDERS in REVERSE ORDER (as shown in the above figure) and that will be our BINARY OUTPUT. 
⧪ Binary To Decimal 

 (a) (100)₂ = ( ... )₁₀  





⧪  Some Questions