## Mixed operations involving addition and subtraction of time

 5.6 Mixed operations involving addition and subtraction of time

Mathematical sentence: $$7\space\text{hours}\space+\space6\space\text{hours}\space-\space4\space\text{hours}\space=\underline{\quad\quad}\,\text{hours}$$

METHOD

$$\begin{array} {rr} \\\space7\;\;\text{hours} \\+\;\;\;\space6\;\;\text{hours} \\\hline\;\;\;1\;3\;\;\text{hours}\\\hline \end{array}$$    $$\Longrightarrow$$      $$\begin{array} {rr} \\\;1\;3\;\;\text{hours} \\-\;\;\;\space4\;\;\text{hours} \\\hline\;\;\;\;9\;\;\text{hours}\\\hline \end{array}$$

## Mixed operations involving addition and subtraction of time

 5.6 Mixed operations involving addition and subtraction of time

Mathematical sentence: $$7\space\text{hours}\space+\space6\space\text{hours}\space-\space4\space\text{hours}\space=\underline{\quad\quad}\,\text{hours}$$

METHOD

$$\begin{array} {rr} \\\space7\;\;\text{hours} \\+\;\;\;\space6\;\;\text{hours} \\\hline\;\;\;1\;3\;\;\text{hours}\\\hline \end{array}$$    $$\Longrightarrow$$      $$\begin{array} {rr} \\\;1\;3\;\;\text{hours} \\-\;\;\;\space4\;\;\text{hours} \\\hline\;\;\;\;9\;\;\text{hours}\\\hline \end{array}$$