3.3.2 Converting between number bases (AQA GCSE Comp Sci)

What is the base of the binary number system? How many unique digits does it use?

• The base is 2. It uses 2 unique digits: 0 and 1.

• The base is 8. It uses 8 unique digits: 0 to 7.

• The base is 10. It uses 10 unique digits: 0 to 9.

• The base is 16. It uses 16 unique digits: 0 to 9 and A to F.

What is the base of the hexadecimal number system? How many unique symbols does it use?

• The base is 16. It uses 16 unique symbols: 0-9 and A-F.

• The base is 10. It uses 10 unique symbols: 0-9.

• The base is 8. It uses 8 unique symbols: 0-7.

• The base is 2. It uses 2 unique symbols: 0 and 1.

In binary, what does each 'bit' represent in terms of powers of 2?

Why is hexadecimal often used in computer science, even though computers only understand binary?

• Hexadecimal is more compact and easier for humans to read and write than binary, and it maps easily to binary (4 bits per hex digit).

• Hexadecimal is the only numbering system computers can process directly.

• Hexadecimal is slower for computers to process than binary, but more accurate.

• Hexadecimal is used because it is incompatible with binary.

What is the largest decimal number that can be represented with 8 bits in binary?

• 255

• 256

• 128

• 512

Convert the binary number 01101011 to its decimal equivalent.

• 107

• 105

• 109

• 111

Convert the decimal number 89 to its 8-bit binary equivalent.

• 01011001

• 01101001

• 10011001

• 01010101

Convert the binary number 10101010 to its decimal equivalent.

• 170

• 154

• 128

• 255

Convert the decimal number 200 to its 8-bit binary equivalent.

• 11001000

• 11000100

• 10011000

• 10101000

What is the decimal value of the binary number 00001111?

• 15

• 8

• 7

• 10