Hisoblang. \( 6 \mathrm{~m} 1 \mathrm{dm} 9 \mathrm{~cm}+2 \mathrm{~m} 7 \mathrm{dm} 8 \mathrm{~cm} \square 9 \mathrm{~m} \) \( 5 \mathrm{~m} 1 \mathrm{dm} 8 \mathrm{~cm}-3 \mathrm{~m} 2 \mathrm{dm} 4 \mathrm{~cm} \square 2 \mathrm{~m} \) \( 18 \mathrm{dm} 9 \mathrm{~cm}+3 \mathrm{~m} 5 \mathrm{~cm} \square 5 \mathrm{~m} 4 \mathrm{~cm} \) \( 84 \mathrm{dm} 2 \mathrm{~cm}-3 \mathrm{~m} 6 \mathrm{dm} 2 \mathrm{~cm} 44 \mathrm{~m} 6 \mathrm{dm} 2 \mathrm{~cm} \)

Calculate \( \left(4.3 \times 10^{14}\right)+\left(8 \times 10^{12}\right) \)

Whork out \( \left(14.2 \times 10^{112}\right)-\left(7 \times 10^{2}\right) \)

7. \( \frac{2}{3}, \frac{1}{4} \) and \( \frac{1}{6} \) are three given rational numbers. Answer the following questions, a) List out the terminating and non-terminating recurring decimals of these rational numbers. b) What is the multiplicative identify of \( \frac{2}{3} \) ? c) Use the given rational numbers to verify the associative properties of addition and multiplication of rational numbers.

b) Let's take a number 260 . (i) Find the square root of 260 by division method. (ii) What is the remainder left in this process? (iii) Subtract the remainder from 260 . Is the difference a perfect square?

1.750 kilometres = how many metres? \( \begin{array}{lll}\text { (1) } 1750 & \text { (2) } 175 & \text { (3) } 17.5\end{array} \)