# Number system conversions

There are many methods or techniques which can be used to convert numbers from one base to another. We’ll demonstrate here the following

• Decimal to Other Base System
• Other Base System to Decimal
• Other Base System to Non-Decimal
• Shortcut method – Binary to Octal
• Shortcut method – Octal to Binary
• Shortcut method – Binary to Hexadecimal
• Shortcut method – Hexadecimal to Binary

### Decimal to Other Base System

Steps:

• Step 1 – Divide the decimal number to be converted by the value of the new base.
• Step 2 – Get the remainder from Step 1 as the rightmost digit (least significant digit) of new base number.
• Step 3 – Divide the quotient of the previous divide by the new base.
• Step 4 – Record the remainder from Step 3 as the next digit (to the left) of the new base number.

Repeat Steps 3 and 4, getting remainders from right to left, until the quotient becomes zero in Step 3.

The last remainder thus obtained will be the most significant digit (MSD) of the new base number.

EXAMPLE

Decimal Number: 2910

Calculating Binary Equivalent:

StepOperationResultRemainder
Step 129 / 2141
Step 214 / 270
Step 37 / 231
Step 43 / 211
Step 51 / 201

Decimal Number: 2910 = Binary Number: 111012.

### Other base system to Decimal System

Steps:

• Step 1 – Determine the column (positional) value of each digit (this depends on the position of the digit and the base of the number system).
• Step 2 – Multiply the obtained column values (in Step 1) by the digits in the corresponding columns.
• Step 3 – Sum the products calculated in Step 2. The total is the equivalent value in decimal.

EXAMPLE

Binary Number: 111012

Calculating Decimal Equivalent:

StepBinary NumberDecimal Number
Step 1111012((1 x 24) + (1 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2111012(16 + 8 + 4 + 0 + 1)10
Step 31110122910

Binary Number: 111012 = Decimal Number: 2910

### Other Base System to Non-Decimal System

Steps:

• Step 1 – Convert the original number to a decimal number (base 10).
• Step 2 – Convert the decimal number so obtained to the new base number

EXAMPLE

Octal Number: 258

Calculating Binary Equivalent:

STEP 1: CONVERT TO DECIMAL

StepOctal NumberDecimal Number
Step 1258((2 x 81) + (5 x 80))10
Step 2258(16 + 5 )10
Step 32582110

Octal Number: 258 = Decimal Number: 2110

STEP 2: CONVERT DECIMAL TO BINARY

StepOperationResultRemainder
Step 121 / 2101
Step 210 / 250
Step 35 / 221
Step 42 / 210
Step 51 / 201

Decimal Number: 2110 = Binary Number: 101012

Octal Number: 258 = Binary Number: 101012

### Shortcut method – Binary to Octal

Steps

• Step 1 – Divide the binary digits into groups of three (starting from the right).
• Step 2 – Convert each group of three binary digits to one octal digit.

EXAMPLE

Binary Number: 101012

Calculating Octal Equivalent:

StepBinary NumberOctal Number
Step 1101012010 101
Step 210101228 58
Step 3101012258

Binary Number: 101012 = Octal Number: 258

### Shortcut method – Octal to Binary

Steps

• Step 1 – Convert each octal digit to a 3 digit binary number (the octal digits may be treated as decimal for this conversion).
• Step 2 – Combine all the resulting binary groups (of 3 digits each) into a single binary number.

EXAMPLE

Octal Number: 258

Calculating Binary Equivalent:

StepOctal NumberBinary Number
Step 1258210 510
Step 22580102 1012
Step 32580101012

Octal Number: 258 = Binary Number: 101012

### Shortcut method – Binary to Hexadecimal

Steps

• Step 1 – Divide the binary digits into groups of four (starting from the right).
• Step 2 – Convert each group of four binary digits to one hexadecimal symbol.

EXAMPLE

Binary Number: 101012

Step 11010120001 0101
Step 2101012110 510
Step 31010121516

Binary Number: 101012 = Hexadecimal Number: 1516

### Shortcut method – Hexadecimal to Binary

Steps

• Step 1 – Convert each hexadecimal digit to a 4 digit binary number (the hexadecimal digits may be treated as decimal for this conversion).
• Step 2 – Combine all the resulting binary groups (of 4 digits each) into a single binary number.

EXAMPLE

Calculating Binary Equivalent:

Step 11516110 510
Step 2151600012 01012
Step 31516000101012

Hexadecimal Number: 1516 = Binary Number: 101012

Some important number systems are as follows.

##### introduction to decimal number system

introduction to decimal number system Decimal number system, also called Hindu-Arabic, or Arabic, number system,  in mathematics, positional numeral system employing...

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