If 536 \(\equiv\) 4 \((mod \ 28)\) and 682 \(\equiv\) 10 \((mod \ 28)\), then find the subtraction and multiplication in modular arithmetic.
1. −146 \(\equiv\) \((mod \ 28)\)
2. \(\equiv\) 40 \((mod \ 28)\)
(Note: Insert a negative sign wherever necessary.)