A small sampling:
int
Whole numbers. Can be from -2,147,483,648 to 2,147,483,647 and uses 32 bits.
float
Allow for decimals. Can be from -3.40282347E + 38 to 3.40282347E + 38 and use 32 bits.
boolean
True or false. Take up very little room - only 1 bit.
For more data types including:
char, unsigned char, byte, work, long, short, double, string, String & Array