Answer:
The expression is equal to zero for the given values
Step-by-step explanation:
<u><em>The correct question is</em></u>
Evaluate start fraction, 1, divided by, 3, end fraction, m, minus, 1, minus, start fraction, 1, divided by, 2, end fraction, n when m=21 and n=12
we have the expression

we know that
To evaluate the expression substitute the given values of m and n
For m=21 and n=12

solve the multiplications

solve the subtraction

therefore
The expression is equal to zero for the given values