Thirty is half of the sum of 4 and a number.
The phrase a number represents an arbitrary variable, let's call it x.
The sum of 4 and a number:
4 + x
Half of this sum means we divide by 2:
(4 + x)/2
Set this equal to 30:
(4 + x)/2 = 30 <-- This is our algebraic expression
The phrase a number represents an arbitrary variable, let's call it x.
The sum of 4 and a number:
4 + x
Half of this sum means we divide by 2:
(4 + x)/2
Set this equal to 30:
(4 + x)/2 = 30 <-- This is our algebraic expression