Evaluate the following:
(a) $⌊6.3⌋ + ⌈−6.3⌉$
(b) $⌊6.3⌋ + ⌊−6.3⌋$
(c) $⌊−6.3⌋ + ⌈−6.3⌉$
(d) $⌊−6.3⌋ + ⌊−6.3⌋$
(a) $\lfloor 6.3 \rfloor + \lceil -6.3 \rceil = 6 + (-6) = 0$
(b) $\lfloor 6.3 \rfloor + \lfloor 6.3 \rfloor = 6 + (-7) = -1$
(c) $\lfloor -6.3 \rfloor + \lceil -6.3 \rceil = -7 + (-6) = -13$
(d) $\lfloor -6.3 \rfloor + \lfloor -6.3 \rfloor = -7 + (-7) = -14$