1. 10 3. What is the cultural significance of this number, and in which cultures? 4. What interesting arithmetic properties does this number possess? 7. What are the interesting geometric properties of this number? Steve Elliott

2. 3. What is the cultural significance of this number, and in which cultures? 10 is the number of commandments in the Old Testament of the Bible, and thus plays a role in Judeo- Christian Culture In the earliest Roman calendars, there were 10 months In US culture, we have Top 10 lists and the FBI’s Ten Most Wanted list

3. 4. What interesting arithmetic properties does this number possess? 10 is the basis of our positional notation for numbers 321 = 3 x 10 2 + 2 x 10 1 + 1 x 10 0 Division by 10 moves a decimal point one position to the left in the dividend 456 / 10 = 45.6 Multiplication by 10 moves a decimal point one position to the right 456 x 10 = 4560

4. 10 is the first triangular number with a center 1 3 6 10 7. What are the interesting geometric properties of this number?