$\"\"$

The equation is $\"\"$ .

What number plus 6 equals to 13 ? (Write the equation as a question)

The solution is 7. $\"\"$

Check whether 7 is a solution.

$\"\"$ (Write the equation)

$\"\"$ (Substitute $\"\"$ )

$\"\"$ (Add: $\"\"$ )

$\"\"$ is the solution of the equation. $\"\"$

$\"\"$ is the solution of the equation.