Definition of dray. : a vehicle used to haul goods; especially : a strong cart or wagon without sides.
Expressions versus Equations. A difference between expressions and equations is what each represents. An expression shows a math relationship. One key to an expression is that there is no solution. An expression does not have an answer. An expression, however, can be evaluated. To evaluate an expression, substitute values for the variables.
Equations are commonly used in mathematics and chemistry. A mathematical equation is a statement that asserts that two different expressions are equal. The expressions are usually separated by an equals sign to show that one side balances the other.A chemical equation is a formula for showing a chemical reaction.