When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 5+1=6$

$\displaystyle \frac{\begin{array}[b]{r}50\\ +\ 10\end{array}}{ \ \ \ \space60}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 5+1=6$

$\displaystyle \frac{\begin{array}[b]{r}55\\ +\ 10\end{array}}{ \ \ \ \space65}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 6+1=$$\displaystyle 7$

$\displaystyle \frac{\begin{array}[b]{r}60\\ +\ 10\end{array}}{ \ \ \ \space70}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 6+1=$$\displaystyle 7$

$\displaystyle \frac{\begin{array}[b]{r}65\\ +\ 10\end{array}}{ \ \ \ \space75}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 7+1=8$

$\displaystyle \frac{\begin{array}[b]{r}70\\ +\ 10\end{array}}{ \ \ \ \space80}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 7+1=8$

$\displaystyle \frac{\begin{array}[b]{r}75\\ +\ 10\end{array}}{ \ \ \ \space85}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 8+1=9$

$\displaystyle \frac{\begin{array}[b]{r}80\\ +\ 10\end{array}}{ \ \ \ \space90}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 7+1=8$

$\displaystyle \frac{\begin{array}[b]{r}75\\ +\ 10\end{array}}{ \ \ \ \space85}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 8+1=9$

$\displaystyle \frac{\begin{array}[b]{r}80\\ +\ 10\end{array}}{ \ \ \ \space90}$

When we add $\displaystyle 10$ to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by $\displaystyle 1$. Mentally, we can add $\displaystyle 1$ to the number in the tens place to find our answer. 

$\displaystyle 8+1=9$

$\displaystyle \frac{\begin{array}[b]{r}85\\ +\ 10\end{array}}{ \ \ \ \space95}$