(a) You are given the expression

$$
1 \diamond 2 \diamond 3 \diamond 4 \diamond 5 \diamond 6 \diamond 7 \text {. }
$$

Determine whether it is possible to replace one of the symbols $\diamond$ with $=$ and the other symbols $\diamond$ with + or - so as to end up with a correct equation.
It is possible; one of many solutions is

$$
1=2+3+4+5-6-7
$$

(b) The same question for the expression

$$
1 \diamond 2 \diamond 3 \diamond 4 \diamond 5 \diamond 6
$$