Binary

Worked examples (9)

• 1State what a computer represents in binary
• 2Calculate the number of patterns from a number of bits
• 3Explain why binary is used rather than denary
• 4Work out how many bits a set of codes needs
• 5Interpret one bit pattern three different ways
• 6Correct the belief that an extra bit adds one more value
• 7Explain why program instructions must also be binary
• 8Assess the claim that a bit pattern is always a number
• 9Evaluate the case for a denary computer

Model answers (9)

• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — extended open-response

Worked examples (9)

• 1Write a value in 8-bit unsigned binary and state the range
• 2Write a negative value in sign and magnitude
• 3Read a two's complement pattern as denary
• 4Negate a number using invert and add one
• 5Read one pattern under all three conventions
• 6Explain the two zeros of sign and magnitude
• 7Explain why two's complement is preferred
• 8Assess sign and magnitude against two's complement
• 9Evaluate a claim about the asymmetric range

Model answers (9)

• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — extended open-response

Worked examples (9)

• 1Convert a binary number to denary
• 2Convert denary to binary by place-value subtraction
• 3Convert denary to binary by repeated division
• 4Complete a mixed conversion table
• 5Convert one number by both methods and compare
• 6Find and correct an error in someone else's conversion
• 7Explain why repeated division produces the bits in reverse
• 8Assess which conversion method a student should use
• 9Evaluate whether conversion is still a skill worth having

Model answers (9)

• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — extended open-response

Worked examples (9)

• 1Add two 8-bit binary numbers
• 2Apply a logical shift left
• 3Apply a logical shift right
• 4Identify overflow in an 8-bit addition
• 5Show that a right shift discards the remainder
• 6Compare a logical and an arithmetic right shift
• 7Explain overflow in a real system
• 8Show where the multiply-by-shifting rule breaks down
• 9Evaluate replacing multiplication with shifts

Model answers (9)

• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — extended open-response

Worked examples (9)

• 1Convert a byte from binary to hexadecimal
• 2Convert a hexadecimal value to binary
• 3Convert a hexadecimal value to denary
• 4Convert binary to hex when the bits do not divide by four
• 5Convert denary to hexadecimal and then to binary
• 6Interpret a hexadecimal colour code
• 7Explain why hexadecimal rather than denary
• 8Diagnose a grouping error
• 9Evaluate the need for hexadecimal

Model answers (9)

• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — short open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — open-response
• ✓Model answer — Edexcel 4CP0 Paper 1 style — extended open-response