To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}11\\ -\ 10\end{array}}{ \ \ \ \ \ \space 1}\)

We can start at \(\displaystyle 11\) and count back \(\displaystyle 10\).

\(\displaystyle 11,10,9,8,7,6,5,4,3,2,1\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}12\\ -\ 10\end{array}}{ \ \ \ \ \ \space 2}\)

We can start at \(\displaystyle 12\) and count back \(\displaystyle 10\).

\(\displaystyle 12,11,10,9,8,7,6,5,4,3,2\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}13\\ -\ 10\end{array}}{ \ \ \ \ \ \space 3}\)

We can start at \(\displaystyle 13\) and count back \(\displaystyle 10\).

\(\displaystyle 13,12,11,10,9,8,7,6,5,4,3\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}14\\ -\ 10\end{array}}{ \ \ \ \ \ \space 4}\)

We can start at \(\displaystyle 14\) and count back \(\displaystyle 10\).

\(\displaystyle 14,13,12,11,10,9,8,7,6,5,4\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}15\\ -\ 10\end{array}}{ \ \ \ \ \ \space 5}\)

We can start at \(\displaystyle 15\) and count back \(\displaystyle 10\).

\(\displaystyle 15,14,13,12,11,10,9,8,7,6,5\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}16\\ -\ 10\end{array}}{ \ \ \ \ \ \space 6}\)

We can start at \(\displaystyle 16\) and count back \(\displaystyle 10\).

\(\displaystyle 16,15,14,13,12,11,10,9,8,7,6\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}17\\ -\ 10\end{array}}{ \ \ \ \ \ \space 7}\)

We can start at \(\displaystyle 17\) and count back \(\displaystyle 10\).

\(\displaystyle 17,16,15,14,13,12,11,10,9,8,7\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}18\\ -\ 10\end{array}}{ \ \ \ \ \ \space 8}\)

We can start at \(\displaystyle 18\) and count back \(\displaystyle 10\).

\(\displaystyle 18,17,16,15,14,13,12,11,10,9,8\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}19\\ -\ 10\end{array}}{ \ \ \ \ \ \space 9}\)

We can start at \(\displaystyle 19\) and count back \(\displaystyle 10\).

\(\displaystyle 19,18,17,16,15,14,13,12,11,10,9\)

To find the missing piece of an addition problem, we can take the biggest number minus the smallest number. 

\(\displaystyle \frac{\begin{array}[b]{r}11\\ -\ 10\end{array}}{ \ \ \ \ \ \space 1}\)

We can start at \(\displaystyle 11\) and count back \(\displaystyle 10\).

\(\displaystyle 11,10,9,8,7,6,5,4,3,2,1\)