
The sentence is “The sum of 7 and 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: If a = b then a – c = b – c.
\
(Subtract 7 from each side)
(Additive inverse property:
)
(Additive identity property:
)
(Subtract:
)
The value of the expression is 16.
\