Simplify: $1-[2-\{5-(4-3-2)\}]$

$\sqrt{? \times 7} \times 18 = 84$

$A$ tin of oil was $\frac{4}{5}$ full when $6$ bottles of oil were taken out. Again,$4$ bottles of oil were poured into it,and it became $\frac{3}{4}$ full. How many bottles of oil can the tin contain?

If the difference between $\frac{4}{5}$ part and $\frac{3}{4}$ part of a number is $4,$ what is the number?

Find the value of $\{(49)^{\frac{3}{2}} + (49)^{\frac{3}{2}}\}$

$4 \frac{3}{4} + 2 \frac{1}{8} + 7 \frac{1}{4} + 3 \frac{7}{8} + 11 \frac{12}{13} = ?$