61. Efectuati transformând termenii î numere zecimale: \( \begin{array}{llll}\text { a) }-2 \frac{1}{2}-0,254 ; & \text { b) }-\frac{3}{4}+0,35 ; & \text { c) }-4,39+4 \frac{2}{5} ; & \text { d) } \frac{5}{8}-1,1\end{array} \)

Consider the product \( 1 \times 2 \times 3 \times 4 \times \ldots \times 30 \). Determine the largest value of \( k \) such that \( 3^{k} \) is a factor of this product.

12. By selling an article for \( ₹ 1,200 \), a seller incurs a loss of \( 20 \% \). What should be the selling price of the same article if the seller wants to earn a profit of \( 20 \% \).

f) \( 0.4^{3} \cdot 10^{-2} \cdot \frac{2^{3}}{4^{0}} \)

3) \( \sqrt{8} \cdot \sqrt{8} \)

a) \( \left(\frac{1}{2}+\frac{2}{3}\right)^{2}= \)