The resulting mass after performing the operation is 3.93 g.
The operation to be performed is +.
To find the resulting mass, we add the two masses:
\[ 16.8 \, \text{g} \, + \, 0.97 \, \text{g} = 17.77 \, \text{g} \]
The resulting mass after performing the operation is 17.77 g.
The operation to be performed is -.
To find the resulting mass, we subtract the second mass from the first:
\[ 0.9 \, \text{g} \, - \, 0.8 \, \text{g} = 0.1 \, \text{g} \]
The resulting mass after performing the operation is 0.1 g.