Express each of the following numbers as a Roman numeral :
(i) 23
(ii) 26
(iii) 29
(iv) 31
(v) 37
(vi) 39
(vii) 40
(viii) 45
(ix) 49
(x) 51
(xi) 63
(xii) 72
(xiii) 79
(xiv) 84
(xv) 89
(xvi) 90
(xvii) 92
(xviii) 99
(xix) 100

Answer

To express the given numbers as Roman numerals, we will break down each number into its components based on the Roman numeral system. The key symbols to remember are:

- I = 1
- V = 5
- X = 10
- L = 50
- C = 100

Now, let's convert each number step by step:

### Step-by-Step Solution:

1. **23**:
- Break down: 20 + 3
- Roman Numerals: XX (20) + III (3) = **XXIII**

2. **26**:
- Break down: 20 + 6
- Roman Numerals: XX (20) + VI (6) = **XXVI**

3. **29**:
- Break down: 20 + 9
- Roman Numerals: XX (20) + IX (9) = **XXIX**

4. **31**:
- Break down: 30 + 1
- Roman Numerals: XXX (30) + I (1) = **XXXI**

5. **37**:
- Break down: 30 + 7
- Roman Numerals: XXX (30) + VII (7) = **XXXVII**

6. **39**:
- Break down: 30 + 9
- Roman Numerals: XXX (30) + IX (9) = **XXXIX**

7. **40**:
- Break down: 50 - 10
- Roman Numerals: L (50) - X (10) = **XL**

8. **45**:
- Break down: 40 + 5
- Roman Numerals: XL (40) + V (5) = **XLV**

9. **49**:
- Break down: 50 - 1
- Roman Numerals: XL (40) + IX (9) = **XLIX**

10. **51**:
- Break down: 50 + 1
- Roman Numerals: L (50) + I (1) = **LI**

11. **63**:
- Break down: 60 + 3
- Roman Numerals: LX (60) + III (3) = **LXIII**

12. **72**:
- Break down: 70 + 2
- Roman Numerals: LXX (70) + II (2) = **LXXII**

13. **79**:
- Break down: 70 + 9
- Roman Numerals: LXX (70) + IX (9) = **LXXIX**

14. **84**:
- Break down: 80 + 4
- Roman Numerals: LXXX (80) + IV (4) = **LXXXIV**

15. **89**:
- Break down: 80 + 9
- Roman Numerals: LXXX (80) + IX (9) = **LXXXIX**

16. **90**:
- Break down: 100 - 10
- Roman Numerals: C (100) - X (10) = **XC**

17. **92**:
- Break down: 90 + 2
- Roman Numerals: XC (90) + II (2) = **XCII**

18. **99**:
- Break down: 90 + 9
- Roman Numerals: XC (90) + IX (9) = **XCIX**

19. **100**:
- Roman Numerals: C (100) = **C**

### Final Roman Numerals:
- (i) 23 = **XXIII**
- (ii) 26 = **XXVI**
- (iii) 29 = **XXIX**
- (iv) 31 = **XXXI**
- (v) 37 = **XXXVII**
- (vi) 39 = **XXXIX**
- (vii) 40 = **XL**
- (viii) 45 = **XLV**
- (ix) 49 = **XLIX**
- (x) 51 = **LI**
- (xi) 63 = **LXIII**
- (xii) 72 = **LXXII**
- (xiii) 79 = **LXXIX**
- (xiv) 84 = **LXXXIV**
- (xv) 89 = **LXXXIX**
- (xvi) 90 = **XC**
- (xvii) 92 = **XCII**
- (xviii) 99 = **XCIX**
- (xix) 100 = **C**