(i) BCD - Binary Coded Decimal.
(ii) EBCDIC - Extended Binary Coded Decimal Interchange Code.
(iii) ASCII - American Standard Code for Information Interchange,
(iv) Unicode.
(v) ISCII - Indian Standard Code for Information Interchange

46₁₀ - 101110₂

The term data comes from the word datum, which means a raw fact. The data is a fact about people. places or some objects

(a) -22₁₀ + 15₁₀

\((1111)_2 \Rightarrow(00001111)_2 \)
\((10110)_2 \Rightarrow(00010110)_2 \)
\(1 \text { 's complement } \quad \quad \quad =11101001 \)
\(2 \text {'s complement } \quad \quad \quad =11101010 \)
\((-22)_{10}+(15)_{10} \quad \quad \quad =11101001 \)
                                       \(= 00001111\)
                                      ______________
                                        1 1 1  0 1 0 1 0
                                      ______________
(b) 20₁₀ + 25₁₀

(10100)₂                       = (11001)₂
8 bit Format of 20₁₀  = 00010100
8 bit format of 25₁₀    = 00011001
20₁₀ + 25₁₀              =    _________
                                       00101101
                                     __________
20₁₀ + 25₁₀ = 00101101₂

(i) There are only two digits in the Binary system, namely, 0 and 1. The numbers in the binary system are represented to the base 2 and the positional multipliers are the powers of 2.
(ii) The left most bit in the binary number is called as the Most Significant Bit (MSB) and it has the largest positional weight.
(iii) The right most bit is the Least Significant Bit (LSB) and has the smallest positional weight.

A numbering system is a way of representing numbers. Each number system is uniquely identified by its base value or radix. Radix or base is the count of number of digits in each number system. Radix or base is the general idea behind positional numbering system.
Example:
Binary Number System - Radix 2
Octal Number System - Radix 8
Deciaml Number System - Radix 10
Hexadecimal Number System - Radix 16.

1101011₂ - 111010₂
1101011
+111010
_______
 110001
_______
= 110001₂

98.46₁₀
1. Integer part

2. Fractional part
0.46 x 2 = 0.92 = 0
0.92 x 2 = 1.84 = 1
0.84 x 2 = 1.68 = 1
0.68 x 2 = 1.36 = 1
0.36 x 2 = 0.72 = 0
0.72 x 2 = 1.44 = 1
98.46₁₀ = (1100010.011101...)₂