1. **Convert Roman numerals to Hindu-Arabic numerals:** (i) XXIII: X = 10, XX = 20, III = 3, so XXIII = 20 + 3 = $23$ (ii) LXIV: L = 50, X = 10, IV = 4, so LXIV = 50 + 10 + 4 = $64$ (iii) XCV: XC = 90, V = 5, so XCV = 90 + 5 = $95$ 2. **Multiply 16 × 9 using doubling and halving:** Doubling 16 and halving 9 stepwise: $16 \times 9$ Halve 9: $\cancel{9} \to 4.5$ (not integer, so keep 9 for now) Instead, halve 16 and double 9: $16 \times 9 = 8 \times 18$ $8 \times 18 = 4 \times 36$ $4 \times 36 = 2 \times 72$ $2 \times 72 = 1 \times 144$ So, $16 \times 9 = 144$ 3. **Round 6343962 to nearest ten thousands:** Look at the thousands digit (3 in 3962), which is less than 5, so round down. Rounded number: $6340000$ 4. **List composite numbers between 15 and 30:** Composite numbers are numbers with factors other than 1 and itself. Between 15 and 30: 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30 5. **Total students in university:** Male students = 5349 Female students = 4559 Total = $5349 + 4559 = 9908$ 6. **Rewrite Hindu-Arabic numerals into Roman numerals:** 63: 50 (L) + 10 (X) + 3 (III) = LXIII 88: 50 (L) + 30 (XXX) + 8 (VIII) = LXXXVIII 41: 40 (XL) + 1 (I) = XLI