$\text{a)}342+\left(342:6\right)+10=342+57+10=409$

$\text{b)}342+\left(342:6\right)+\left(342:19\right)=342+57+18=417$

$\text{c)}342+\left(342:6\right)+\left(\left(342:6\right):3\right)=342+57+19=418$

$\text{d)}342+\left(342:6\right)+\left(342+\left(342:6\right)-380\right)=342+57+19=418$