$\"\"$ $\"\"$

The sentence is “The sum of 7 and a number is 23”

Let n be the number

The word sum indicates addition, and the symbol is $\"\"$

Thus, the numerical expression is “ $\"\"$ ”

The equation is, $\"\"$ $\"\"$

Subtraction property of equality: Subtract 7 from each side.

$\"\"$

$\"\"$ (Apply additive inverse property: $\"\"$ )

$\"\"$ (Apply additive identity property: $\"\"$ )

$\"\"$ (Subtract: $\"\"$ ) $\"\"$

The value of the expression is 16.