Variables Math

In computer science, variables

• are always represented by the letter x

• are an unknown that you are trying to solve for

• are a placeholder for information that can change in the program

• cannot be used with conditionals and functions.

Variables can be used

• only once in a program

• only once and must be used within conditionals

• only in "for loops"

• can be used multiple times in a program

A "constant" variable

• sets the value of the variable once at the beginning of the program and never changes

• sets the value of the variable only at the end of the program

• is never useful when writing an algorithm

• is an advanced use of variables

When we initialize a variable, we

• define the set of commands that the variable will run when called

• give the variable a name and an initial value

• always set the variable to the starting value of 0

• give it initials, like a nickname

How do you declare a variable in App lab

• dec

• var

• variable

• declare

What does this sign represent?

• Adding two or more numbers.

• subtracting two numbers.

• multiplying two or more numbers.

• dividing two or more numbers.

What do these sign represent?

• Is equal to

• Greater than and less than equal to

• Greater than and Greater than Equal to

• Does not represent anything

What does this sign represnt?

• Subtract

• Add

• Multiply

• Mod

What is the value of the variable for dogs
dogs =10
dogs= 20 +10

• 10
• 20
• 30
• none

What is the value of the following variable for dogs
dogs = 10
cats = 20
dogs = cats + dogs

• 10
• 20
• 30
• none