Past Paper Questions
Jan 2011
3 (a) Calculate the denary value of the 8-bit binary number 10010111.
You must show your working.
128 64 32 16
1
0 0
1 0
128
+
1
1
1
16
151
[2]
June 2011
6 (a) Convert the hexadecimal number 6A to denary.
You must show your working.
6 = 0110
A = 1010 therefore
128 64 32 16
0
1 1 0
64+ 32 +
8
1
8
4
0
+
2
1
2
6A = 01101010
1
0
= 106
............................................................................................................................................. [2]
(b) Convert the hexadecimal number 6A to binary.
6 = 0110
A = 1010 therefore
6A = 01101010
............................................................................................................................................. [2]
(c) Convert the binary number 00111101 to hexadecimal.
0011 = 3
1101 = D
3D
............................................................................................................................................. [2]
(d) Explain why hexadecimal numbers are often used to represent binary numbers.
As a short hand for binary so that we will make less mistakes when writing long binary
numbers.
............................................................................................................................................. [2]
1