Let represent the number.
The word “less” represents subtraction and the symbol is "".
Two-thirds of a number indicates .
The word “is” indicates the symbol “”.
Let = number.
Rewrite the sentence into equation,
\The equation is .
According to subtraction property of equality: Subtract 13 from each side.
\ (Apply commutative property of addition:
)
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Subtract:
)
According to division property of equality: Divide each side by 4.
\ (Cancel common terms)
(Divide:
)
Check:
\To check the solution, substitute in original equation.
(Multiply:
)
(Add:
)
Compare the values, the equation is true.
The value of .