### 2:
1. Our modern numerical system is based on Hindu-Arabic numerals.
2. The numeral system has ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
3. The earliest known mathematical symbol is the Ishango bone.
4. Egyptians used a base-10 numerical system for practical measurements.
5. Abacus is one of the earliest counting devices in history.
6. Mathematical notation simplifies complex calculations and measurements.