1. Which number is NOT a factor of 35 ? 7 5 6 1

The number 6 is NOT a factor of 35. A factor is a whole number that can be divided evenly into another number. In this case, 35 can be divided by 1, 5, and 7, resulting in whole numbers (35, 7, and 5 respectively), but dividing 35 by 6 leaves a remainder, which means 6 isn’t a factor. Now let's look at some historical tidbits! The concept of factors dates back to ancient civilizations, where mathematicians and traders alike needed to understand how to divide goods fairly. The Greeks, particularly Euclid, contributed significantly to number theory, laying the groundwork for the understanding of factors and multiples that we still use today. Numbers were not just for calculations; they often held significance in trade, art, and even astrology!