Encoding Schemes and Number System
Class 11 · Computer Science
4 ideas in Class 11 Computer Science, explained in plain words, with games and quizzes to practise.
Binary Basics
Part of: Binary and Decimal
Binary uses 0, 1 with place values doubling; convert by weights or division; bits count capacity.
Why it matters. Machine language read. Values converted.
Formulas
- Place values double leftwards: 1, 2, 4, 8, 16
- n bits hold 2^n different values
- Leftmost 1 in 1101 carries weight 8
Key words
- Binary system
- : Two-digit system of 0 and 1 used by computers.
- Bit
- : One binary digit, 0 or 1.
- Base 2
- : Value two, fixing binary place doubling.
- Place value
- : Position weight used to convert binary to decimal.
- Bit capacity
- : Total values fitting in a fixed bit count.
Try it in two minutes
- List place values.
- Add set weights.
- Divide for binary.
Try at home. Convert your age.
Octal and Hex
Part of: Binary and Decimal
Octal base 8 groups 3 bits; hex base 16 groups 4 bits with A to F; convert via binary grouping.
Why it matters. Short forms read. Groups convert.
Formulas
- Octal groups binary in threes from the right
- Hex groups binary in fours, using A to F for 10 to 15
- Hex FF = 255 and octal 17 = 15
Key words
- Octal system
- : Base-eight shorthand grouping three bits.
- Hex system
- : Base-sixteen shorthand grouping four bits.
- Hex letters
- : Letters A to F standing for ten to fifteen.
- Binary grouping
- : Regrouping bits to read octal or hex quickly.
Try it in two minutes
- Group the bits.
- Read each group.
- Convert via binary.
Try at home. Group a binary string.
Encoding Schemes
Part of: Encoding and Arithmetic
ASCII codes English in 7 bits; ISCII Indian scripts; Unicode covers world scripts in wider bytes.
Why it matters. Text stored numeric. Scripts covered.
Formulas
- ASCII of A = 65, and a to z follow in order
- 7-bit ASCII covers English; Unicode covers world scripts
Key words
- Encoding
- : Text stored as numeric codes.
- ASCII
- : 7-bit code for English letters, digits and symbols.
- ISCII
- : Code made for Indian scripts.
- Unicode
- : Single scheme covering world scripts together.
- UTF-8
- : A byte-wise storage form of Unicode.
Try it in two minutes
- Text to numbers?
- Which scheme?
- How wide?
Try at home. Find char codes.
Binary Arithmetic
Part of: Encoding and Arithmetic
Binary adds like decimal with carries: 1 plus 1 is 10; add column-wise, carry overs.
Why it matters. Machine maths understood. Carries traced.
Formulas
- 1 + 1 = 10 with carry 1 to the next column
- Column sums of 2 or 3 write a digit and carry over
- Check binary sums by converting both sides to decimal
Key words
- Binary addition
- : Two-symbol adding where 1 + 1 becomes 10.
- Binary carry
- : Extra digit passed left when a column reaches two.
- Column-wise adding
- : Adding each column from right to left with carries.
Try it in two minutes
- Align columns.
- Add with carry.
- Check in decimal.
Try at home. Add two binaries.
What your child will practise
- Binary Arithmetic: Candy Puzzle (Clue Puzzle)
- Binary Arithmetic: Candy Quick Fire (Quick Fire)
- Binary Basics: Desert Puzzle (Clue Puzzle)
- Encoding Schemes: Candy Quest (Flip and Match)
- Octal and Hex: Ocean Quick Fire (Quick Fire)
- Quiz: Binary Arithmetic (8 questions)
- Quiz: Binary Basics (8 questions)
- Quiz: Encoding Schemes (8 questions)
- Quiz: Octal and Hex (8 questions)