n+3/21=14/21 n=11/21 Hope this helps!

[latex]n+ \frac{1}{7}= \frac{2}{3}\\ \\n = \frac{2}{3}-\frac{1}{7}\\ \\n=\frac{14}{21}-\frac{3}{21}\\ \\n=\frac{11}{21}[/latex]