What is a math expression?

Answer 1

An expression is the sum (or difference) of two or more terms. Example 3x + 2y is an expression.

It is a mathematical statement e.g 7=6+1 THE WHOLE THING IS AN EQUATION but the 6+1 is a expression.You can only have an expression if there is not an = sign

Yes the 6 + 1 part is an expression. If you have an = sign or any of the other inequality symbols (<, >,...) it is no longer an expression but a full math sentence.

Answer 2

in maths, an expression is an equation with no equals sign.

equation.............2+2=4

expression..........2+2