4. . Calculate the percentage of the following numbers: \( \begin{array}{ll}\text { a) Find } 10 \% \text { of } 20= & \text { b) Find } 20 \% \text { of } 10= \\ \text { c) Find } 25 \% \text { of } 4= & \text { d) Find } 50 \% \text { of } 50= \\ \text { e) Find } 25 \% \text { of } 20= & \text { f) Find } 50 \% \text { of } 80=\end{array} \)

1) \( a=8 \frac{2}{5} \) vo \( b=1 \frac{1}{20} \) olduqda \( 0,2 \cdot(a: b) \) ifadosinin qiymotini tapın. 2) \( a=1 \frac{3}{23} \) vo \( b=4 \frac{5}{23} \) olduqda \( (b: a): 2 \frac{1}{2} \) ifadosinin qiymotini tapın.

17. Without using a calculator evaluate. 18. The lengths of three wires were \( 30 \mathrm{~m}, 36 \mathrm{~m} \) and 84 m . Pieces of wire of equal lenght were cat from the three wires. Calculate the least number of pieces obtained.

Умножь: \( \frac{2}{17} \cdot 4=\frac{\square}{\square} \).

Lelt's Discuss A wristwatch was sold for Php 2500.00 with a \( 20 \% \) discount. What was the original price of the wristwatch? Solution: \( D R=20 \%, \mathrm{SP}=2,500, \mathrm{OP}= \) ?

5. \( \sqrt{ } 4 \cdot \sqrt{ } 32 \)