How do you Convert a decimal 25 to hexadecimal?

Answer 1

Step 1: To get 25 in Hex, simply split the two numbers (2 and 5, place the 2 on the left and the 2 on the right of the page to split them). Ie. 2 5.

Step 2: Next, write down 1, 2, 4, 8 (from right to left) on both sides (for the 2 and the 5). Ie. 8 4 2 1 (repeated for right side).

Step 3: Try to work out how many of each digit is required to make the number. For example, to make the 2 (from the number 25), I required no (8), no (4), 1 (2) and no (1). (eg. 0 0 1 0 should be the answer for the 2 on the left , and 0 1 0 1 for the 5 on the right). Use a small line above the 1, 2, 4, 8 to write down these values.

Step 4: When you see a 1 over a number (eg 1 over the number 8) write it down and add to any other number which also has a one above it.
In this case (on the left hand side of the page, you should have only one 1, which is over the number 2). For example on the left you would add 0+0+1+0=2 (because the number 1 is over the number 2, it is used as an answer for the left hand side).
On the right hand side you should have: 4+1=5 (the two 1's are over the 4 and the 5, therefore this is added and the answer is 5).

Step 5: Add both answers together. In this case you should be adding 2+5=7.

Step 6: 255-Answer, ie. 255-7=248.

Step 7: Make a table containing the digits: 1, 2, 4, 8, 16, 32, 64 & 128 (from right to left like before).

Step 8: Under each digit place either a 1 or a zero (1 where number is requried and 0 where a number is not required). In this case your binary digits should read: 1 1 1 1 and 1 0 0 0. When the numbers are added up, it should equal 248 (answer from step 6). Ie. 248+64+32+16+8=248 (all other numbers, ie. 4, 2and 1 are not required, so a zero is placed underneath them in the table).

Step 9: Write down 8, 4, 2, 1 for both sides again. So you should have 8 4 2 1 on the left and the right (remember the left digits represent 2 and the right digits represent 5).

Step 10:
Write (left side):
1 over the 8
1 over the four
1 over the 2
1 over the 1
It should look like: 1 1 1 1
8+4+2+1=15 (if there was a zero, only 3 numbers would be added).

Write (right side):
1 over the 8
0 over the 4
0 over the 2
0 over the 1
It should look like: 1 0 0 0
8+0+0+0=8 (because there is a 1 over the zero, it is neede to discover the final hex value).

Final answer (hex value)= F8

Note: If the final answer was 1 and 3, it would be written as 13. But because a red green or blue can only be represented with 2 digits only, a letter is uses instead of the two digits.

Final Notes:

• Value ranges from 0-255.
• RGB: To make a colour, each colour is represented by two decimal values or hex values, eg. 99 (decimal) or FF (hex) for red; 10 (dec) or A (hex) for green, and 15 (dec) or F (hex) for blue.
  
• Hex values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F.