= Solution
For <bosonic creation operators> and <bosonic annihilation operators>, the <canonical commutation relations> are
$$
[a_i,a_j^\dagger]=\delta_{ij},\qquad[a_i,a_j]=[a_i^\dagger,a_j^\dagger]=0.
$$
For <fermionic annihilation operators> and their adjoints, the <canonical anticommutation relations> are
$$
\{f_i,f_j^\dagger\}=\delta_{ij},\qquad\{f_i,f_j\}=\{f_i^\dagger,f_j^\dagger\}=0.
$$
The respective <number operators> are $n_i=a_i^\dagger a_i$ and $n_i=f_i^\dagger f_i$. Their allowed <eigenvalues> are $\boxed{0,1,2,\ldots\text{ for bosons};\quad0,1\text{ for fermions}}$. In the fermionic case $n_i^2=n_i$, so its <eigenvalues> must satisfy $n^2=n$; this is the single-mode <Pauli exclusion principle>.
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