Answer
You are adding the two values $+7$ and $+14,$ which should produce the
value $ +21$. But when you add the two values together, you get 10101,
which is a negative value because the leftmost digit is a $1 .$ In fact, it is
the value $-5 .$ What happened is that we got an arithmetic overflow. The
value $+21$ is too big to represent in sign/magnitude with only five digits.
Work Step by Step
You are adding the two values $+7$ and $+14,$ which should produce the
value $ +21$. But when you add the two values together, you get 10101,
which is a negative value because the leftmost digit is a $1 .$ In fact, it is
the value $-5 .$ What happened is that we got an arithmetic overflow. The
value $+21$ is too big to represent in sign/magnitude with only five digits.