I was sure I had this here already but I can’t find it.

Here are the main formula we used in the computer systems unit

• Largest number with n bits = 2ⁿ-1
• No of memory locations/different colours = 2ⁿ
• Coloumn heading in a binary number at n bit =2^n-1
• Size of bitmap = no. of Horizontal pixels X no. of Vertical pixels X Colour Depth
• No. of pixels = DPI X size in inches
• Total storage capacity = no. of memory locations X location size.

You should also be able to convert from bits, Bytes, Kilobytes, Megabytes, Gigabytes & Terabytes.

• Bit= 1/0 (Binary digIT)
• 1 Byte = 8 Bits
• 1 Kilobytes= 1024 Bytes  (2¹⁰)
• 1 Megabytes= 1024 KB  (2²⁰)
• 1 Gigabytes = 1024 MB  (2³⁰)
• 1 Terabytes = 1024 GB  (2⁴⁰)

For colour depth

• 8 bits = 256 colours (2⁸)
• 16 bits = High Colour 65,536 colours (2¹⁶)
• 24 bits = True Colour 16,777,216 colours (2²⁴)