We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 54-38=16$

$\displaystyle {\color{Teal} 54-39=15}$

$\displaystyle 54-40=14$

$\displaystyle 54-37=17$

$\displaystyle 54-36=18$

Because we are looking for the number that when subtracted from $\displaystyle 54$ equals $\displaystyle 15$, our correct answer is $\displaystyle 39$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 39-17=22$

$\displaystyle {\color{Teal} 39-18=21}$

$\displaystyle 39-19=20$

$\displaystyle 39-20=19$

$\displaystyle 39-21=18$

Because we are looking for the number that when subtracted from $\displaystyle 39$ equals $\displaystyle 21$, our correct answer is $\displaystyle 18$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 27-22=5$

$\displaystyle {\color{Teal} 27-21=6}$

$\displaystyle 27-20=7$

$\displaystyle 27-23=4$

$\displaystyle 27-24=3$

Because we are looking for the number that when subtracted from $\displaystyle 27$ equals $\displaystyle 6$, our correct answer is $\displaystyle 21$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 45-9=36$

$\displaystyle 45-10=35$

$\displaystyle {\color{Teal} 45-11=34}$

$\displaystyle 45-12=33$

$\displaystyle 45-13=32$

Because we are looking for the number that when subtracted from $\displaystyle 45$ equals $\displaystyle 34$, our correct answer is $\displaystyle 11$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 83-59=24$

$\displaystyle 83-58=25$

$\displaystyle {\color{Teal} 83-57=26}$

$\displaystyle 83-56=27$

$\displaystyle 83-55=28$

Because we are looking for the number that when subtracted from $\displaystyle 83$ equals $\displaystyle 26$, our correct answer is $\displaystyle 57$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 65-35=30$

$\displaystyle 65-34=31$

$\displaystyle {\color{Teal} 65-36=29}$

$\displaystyle 65-37=28$

$\displaystyle 65-38=27$

Because we are looking for the number that when subtracted from $\displaystyle 65$ equals $\displaystyle 29$, our correct answer is $\displaystyle 36$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 99-52=47$

$\displaystyle 99-53=46$

$\displaystyle {\color{Teal} 99-51=48}$

$\displaystyle 99-54=45$

$\displaystyle 99-55=44$

Because we are looking for the number that when subtracted from $\displaystyle 99$ equals $\displaystyle 48$, our correct answer is $\displaystyle 51$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 85-27=58$

$\displaystyle 85-26=59$

$\displaystyle {\color{Teal} 85-32=53}$

$\displaystyle 85-29=56$

$\displaystyle 85-28=57$

Because we are looking for the number that when subtracted from $\displaystyle 85$ equals $\displaystyle 53$, our correct answer is $\displaystyle 32$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 89-27=62$

$\displaystyle 89-28=61$

$\displaystyle {\color{Teal} 89-24=65}$

$\displaystyle 89-25=64$

$\displaystyle 89-26=63$

Because we are looking for the number that when subtracted from $\displaystyle 89$ equals $\displaystyle 65$, our correct answer is $\displaystyle 24$

We can use substitution to determine the value of $\displaystyle x$. 

$\displaystyle 79-7=72$

$\displaystyle 79-6=73$

$\displaystyle {\color{Teal} 79-5=74}$

$\displaystyle 79-4=75$

$\displaystyle 79-8=71$

Because we are looking for the number that when subtracted from $\displaystyle 79$ equals $\displaystyle 74$, our correct answer is $\displaystyle 5$