Answer: No. Phone numbers are considered numbers, but it doesn’t make sense to perform any mathematical operations on these numbers like adding or taking an average. Have the students list some other numbers that wouldn’t be consider mathematical objects (SS #, zip code, credit card #)
Answer: Counting, keeping track of the number of animals in a heard or other belongings. Before there were number systems, early sheppard’s actually used stones and two buckets to keep track of their sheep. When they migrated in the morning they would fill up one buck with one stone for each sheep. Then when they returned in the evening, they would move the one stone from the full bucket to the empty bucket for each sheep to make sure none of the sheep went missing.
We use the Hindu-Arabic symbols today is because they were developed in India, where most of the world’s, including European countries, visited for trading goods and money.
We don’t start counting with zero, which was not introduced as a symbol for almost 2000 years after the first number set. The natural numbers are also missing negative numbers.
Answer: Zero is also a place holder in our number system. It allows us to see the difference between 21 and 201 and 210.
The first place in history we saw the concept of negative numbers was in China and India to maintain trading accounts (300 B.C.). They used red numbers to represent positives, and black for negative (which is opposite of what we use in America today). Until recent history many culture tried to avoid using negative numbers explicitly. The history books tell us that Julius Caesar was born in 100 B.C., not –100. The subterranean levels in a parking garage often have names like B1 and B2. Temperatures are one of the few exceptions where we actually use the negative symbol. (Note: They use the letter Z instead of I because the use I for irrational numbers. Not clear where the Z comes from).
![2.1 Number Sense Natural, Whole, and Integer Number Systems ,[object Object],[object Object],[object Object],[object Object]](https://image.slidesharecdn.com/22-1intro-numbersense-110614184610-phpapp02/85/2-21-intro-number-sense-1-320.jpg)
![[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)