expression and equation

• what is a expression?

  an expression is a problem without full information or without a equal sign.
• what is an ewuation?

  is a problem that is complete of information and has an equal sign
• x + 2, y - 3 and x - 18 , what is this example?

  expression
• x - 5 = 10, y + 15 = 30, what is this example?

  equation