Mathematics - Number Theory - Modular arithmetic - Mod Computations

10 problems: (1-2) Find: 23 mod 7, 100 mod 13. (3-4) Add: (15+19) mod 6, (37+48) mod 10. (5-6) Multiply: 8×7 mod 5, 13×17 mod 9. (7) Power: 3⁴ mod 5. (8) Find inverse: 4⁻¹ mod 11. (9) 'What day of the week is it 100 days after Monday?' (10) 'Last digit of 7²⁰²³?' (Find pattern of 7ⁿ mod 10: 7,9,3,1,