1. $-(-4)^3-(-4)^2+6(-4)-21$
$64-16-24-21$
$3$
2. $(-6)^2+3(-6)-11$
$36-18-11$
$7$
3. $-5(-1)^4-11(-1)^3-9(-1)^2-(-1)-5$
$-5+11-9+1-5$
$-7$
4. $(5)^4-5(5)^3-(5)+13$
$625-625-5+13$
$8$
5. $(-3)^2+9(-3)+23$
$9-27+23$
$5$
6. $-6(6)^3+41(6)^2-32(6)+11$
$-1296+1476-192+11$
$-1$
7. $(6)^4-6(6)^3+(6)^2-24$
$1296-1296+36-24$
$12$
8. $(-6)^4+8(-6)^3+14(-6)^2+13(-6)+5$
$1296-1728+504-78+5$
$-1$
9. $\phantom{a}$
$\begin{array}[t]{rrr} -5p^4&+&5p \\ +8p^4&-&8p \\ \hline 3p^4&-&3p \end{array}$
10. $\phantom{a}$
$\begin{array}[t]{rrr} 5m^3&+&7m^2 \\ -6m^3&+&5m^2 \\ \hline -m^3&+&12m^2 \end{array}$
11. $\phantom{a}$
$\begin{array}[t]{rrr} 5p^3&+&1 \\ 8p^3&-&1 \\ \hline 13p^3&& \end{array}$
12. $\phantom{a}$
$\begin{array}[t]{rrr} 6x^3&+&5x \\ -6x^3&-&8x \\ \hline &&-3x \end{array}$
13. $\phantom{a}$
$\begin{array}[t]{rrrrr} 5n^4&+&6n^3&& \\ -5n^4&-&3n^3&+&8 \\ \hline &&3n^3&+&8 \end{array}$
14. $\phantom{a}$
$\begin{array}[t]{rrrrr} &&8x^2&+&1 \\ x^4&+&x^2&-&6 \\ \hline x^4&+&9x^2&-&5 \end{array}$
15. $\phantom{a}$
$\begin{array}[t]{rrrrr} 2a^4&&&+&2a \\ 5a^4&-&3a^2&-&4a \\ \hline 7a^4&-&3a^2&-&2a \end{array}$
16. $\phantom{a}$
$\begin{array}[t]{rrrrr} 8v^3&+&6v&& \\ 4v^3&-&3v&+&3 \\ \hline 12v^3&+&3v&+&3 \end{array}$
17. $\phantom{a}$
$\begin{array}[t]{rrrrr} 4p^2&-&2p&-&3 \\ -3p^2&+&6p&-&3 \\ \hline p^2&+&4p&-&6 \end{array}$
18. $\phantom{a}$
$\begin{array}[t]{rrrrr} 8m^4&+&4m&+&7 \\ -5m^4&-&6m&-&1 \\ \hline 3m^4&-&2m&+&6 \end{array}$
19. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 4n^4&&&+&2n^2&+&3 \\ -4n^4&+&n^3&-&7n^2&& \\ \hline &&n^3&-&5n^2&+&3 \\ \end{array}$
20. $\phantom{a}$
$\begin{array}[t]{rrrrr} 2x^4&+&7x^3&+&7x^2 \\ -8x^4&+&6x^3&-&7x^2 \\ \hline -6x^4&+&13x^3&& \end{array}$
21. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 8r^4&-&5r^3&+&5r^2&& \\ -7r^4&+&2r^3&+&2r^2&+&1 \\ \hline r^4&-&3r^3&+&7r^2&+&1 \end{array}$
22. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 4x^3&-&7x^2&+&x&& \\ 6x^3&+&x^2&+&2x&-&8 \\ \hline 10x^3&-&6x^2&+&3x&-&8 \end{array}$
23. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 7n^4&&&+&2n^2&-&2 \\ 2n^4&+&2n^3&+&4n^2&+&2 \\ \hline 9n^4&+&2n^3&+&6n^2&& \end{array}$
24. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 4b^4&+&7b^3&&&-&4b \\ -2b^4&-&8b^3&+&4b^2&+&8b \\ \hline 2b^4&-&b^3&+&4b^2&+&4b \\ \end{array}$
25. $\phantom{a}$
$\begin{array}[t]{rrrrrrrrr} &&7b^3&&&-&b&+&8 \\ -3b^4&&&-&7b^2&-&7b&+&8 \\ &&6b^3&&&-&3b&+&3 \\ \hline -3b^4&+&13b^3&-&7b^2&-&11b&+&19 \end{array}$
26. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} -3n^4&-&8n^3&&&+&1 \\ 7n^4&+&3n^3&-&6n^2&+&2 \\ 8n^4&+&4n^3&&&+&7 \\ \hline 12n^4&-&n^3&-&6n^2&+&10 \end{array}$
27. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} 8x^4&+&2x^3&+&2x&& \\ -x^4&-&2x^3&+&2x&+&2 \\ -5x^4&-&x^3&-&8x&& \\ \hline 2x^4&-&x^3&-&4x&+&2 \\ \end{array}$
28. $\phantom{a}$
$\begin{array}[t]{rrrrrrr} -5x^4&-&4x^2&+&6x&& \\ 4x^4&+&7x^2&-&2x&+&8 \\ 4x^4&+&6x^2&&&-&8 \\ \hline 3x^4&+&9x^2&+&4x&& \end{array}$