What should come in place of the question mark (?) in the following question ?
$$\frac{9}{10}+\frac{3}{11}+\frac{7}{15}= ?$$
$$\sqrt[3]{42875}-?=21$$
$$\frac{57}{67}\times\frac{32}{171}\times\frac{45}{128}=?$$
$$\frac{1}{4}$$th of $$\frac{1}{2}$$ of $$\frac{3}{4}$$th of 52000=?
$$(7921\div178)-5.5=\sqrt{?}$$
38% of 4500-25% of ?=1640
$$(5863-\sqrt{2704})\times0\cdot5=?$$
$$(?)^{2}+15^{2}-33^{2}=97$$
25639-5252-3232=?
$$283 \times56+252=20 \times?$$