The document introduces programming concepts using JavaScript, focusing on arithmetic operations, variable assignments, and expressions. It includes examples of basic calculations and evaluations, as well as homework assignments for practicing the implementation of these concepts. The document serves as a primer for beginners learning to communicate with computers through programming languages.

1. chapter 1
communicating with your computer

2. English
French
Spanish
Chinese

3. We talk to computers with
programming languages.
c++

4. JavaScript

6. Chakra V8 SpiderMonkey

7. http://repl.it/languages/JavaScript

8. input output

9. input output
JavaScript Code text, behavior

10. what is 2 + 2?
4!

11. 2 + 2;

12. 2 + 2;
expression

13. 2 + 2;
expression
semicolon ends
the expression

14. 2 + 2;
expression
semicolon ends
the expression
arithmetic operator

15. 2 + 2;
expression
semicolon ends
the expression
arithmetic operator
value value

16. 2 + 2;
evaluates to
the value 4

17. var sum = 2 + 2;

18. var sum = 2 + 2;
expression
assignment operator
identifier
keyword to declare
new variable

19. sum;
evaluates to
the value 4

20. var sum = 2 + 2;
sum = 4 + 10; // sum now equals 14

21. var sum = 2 + 2;
sum = 4 + 10; // sum now equals 14
comment, ignored by the JavaScript engine

22. var sum = 2 + 2;
sum = 4 + 10; // sum now equals 14
sum + 10; // evaluates to 24

23. var sum = 2 + 2;
sum = 4 + 10; // sum now equals 14
sum = sum + 10; // sum equals 24

24. 10 - 6; // evaluates to 4
10 * 4; // evaluates to 40
10 / 2; // evaluates to 5

25. 10 - 6; // evaluates to 4
10 * 4; // evaluates to 40
10 / 2; // evaluates to 5
subtraction operator
multiplication operator
division operator

26. Review

27. What are the values in this expression?
1 + 45 + 10 + 20;

28. What does this expression “evaluate” to?
99 + 1 + 10;

29. What does this expression “evaluate” to?
// 34 + 5 + 1;

30. What value is the variable bottles set to?
var cans = 2 + 10;
var bottles = 2 + cans - 10 - cans;

31. Homework #1
Write a JavaScript
expression which adds
5 to 10.
This expression
should evaluate to 15.
Use www.repl.it to
write your code.

32. Homework #2
Define three variables. One
should hold your age, one
should hold your favorite
number, and one should hold
the number of siblings you
have.
Next, define a new variable
which stores the result of
adding the previous three
variables together.

33. Homework #3
Define a variable to hold the number
of hours in a day.
Multiply this value by 7 to get the
number of hours in a week. Assign
this to a new variable.
Next, multiply this by the number of
weeks in a year (52) and assign the
result of this in a new variable.
Finally, divide this number by the
number of days in a year (365). What is
the result?

34. Intro to Programming
with Seth McLaughlin