- What is an Integer? {...,-1,0,1,2,...}
- What is an Int? {-maxint-1, -maxint, ..., -1,0,1,2, ..., maxint}
- What is a Real?
- What is a Float? Anything you can write in scientific notation.
- The computer usually uses base 2 or base 16 scientific notation.
- Python Long Int. { ..., -1, 0,1,2, ...} up to the available memory.
- Example: 2147483648L notice the trailing L
- Python does automatic conversion in mixed expressions. Eg: 9.0/5, 2**65
- Every number literal has a type. Every expression has a type. Every literal has a type. Sensible mixed expressions have a type, non-sensible mixed expressions give an error. Eg: "hi" + "there" makes sense as string concatenation. "hi"/3 makes no sense.
- Python type command is handy for checking types. Eg: type(3/4.0), type(3/4).
- Built in operators on numeric types: + - * / ** % abs(). Try each of these. Especially try 2**0.5.
- See p470 Python language built-in operator summary.

- Counting in Binary.
- Word size and maxint.
- Negative numbers in two-s complement.
- Storage of numbers in base 2 words of 32 or 64 bits.
- Overflow of Int, discussion on page 63-64.
- Long integers in Python

- At the top of your program - import math.
- Get the functions shown on p470, built-in math functions.
- Don't for get to say math.sqrt(2), ie, using library prefix.
- Try math.pi, math.log(x), math.log10(x), math.exp(x). Compare with the built-in operator **. Try math.exp(3) vs math.e ** 3
- Try math.log(math.exp(3)) and math.exp(math.log(3))

- int(7.5)
- round(7.5)
- float(3)
- float(3/4)
- float(3)/4
- A way to average ... (3+4)/2
- float(3+4)/2
- round(-3.64)
- int(-3.64)
- long(3.9)
- long(round(3.9))

- factorial
fact=1 for n in [2,3,4,5,6] fact = fact * n

- factorial again
fact=1 for n in range(2,7) # 2,3,4,5,6 fact = fact * n

- More range(start, end, inc) examples