← Class 8 unitsComputational Thinking
Class 8
Chapter 3: A Story of Numbers
Different cultures invented different number systems. Roman numerals (I, V, X, L, C, D, M) are non-positional. Our everyday system is positional with base 10 — the value of a digit depends on its place.
Learning outcomes
- Trace how number systems evolved historically
- Compare positional vs non-positional systems
Activities
- Mini-poster on number systems
Worked examples
Read through these first, then try the practice below.
Example 1 — Roman to decimal
What number is XIV?
Solution: X is 10, IV is 4 (5 − 1). XIV = 14.
Example 2 — Place value
In the number 4567, what is the place value of the digit 5?
Solution: 5 is in the hundreds place: 5 × 100 = 500.
Self-do practice
Question 1 of 3 · Score 0/0Convert XL to a decimal number.
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