If the sum is 18 and you turned over a 7 , how would you find the new sum? Share your strategy.

Mrs. Thapa is a teacher. She can walk \( 2 \frac{1}{4} \mathrm{~km} \) in one hour. How long does he take to go to her school which is \( 4 \frac{1}{2} \mathrm{~km} \) for from her home?

With the use of a calculator, evaluate each of the follov 3 significant figures. (a) \( \left(8.59 \times 10^{-7}\right) \times\left(0.392 \times 10^{5}\right) \) (b) \( \left(8.05 \times 10^{6}\right) \div\left(7 \times 10^{-2}\right) \) (c) \( 3.2 \times 10^{6}+1.8 \times 10^{4} \) (d) \( 1.97 \times 10^{7}-2.02 \times 10^{5} \)

Ratios \( 3: 6= \)

The speed of a motorbike decreases from 60.5 km per hour to 40.8 km per hour in 5 minutes. Find the decrease in speed in a minute. \( \begin{array}{ll}\text { A. } 3.24 \mathrm{~km} \text { sejam } & \text { C. } 3.94 \mathrm{~km} \text { sejam } \\ 3.24 \mathrm{~km} \text { per hour } & 3.94 \mathrm{~km} \text { per hour } \\ \text { B. } 3.64 \mathrm{~km} \text { sejam } & \text { D. } 3.98 \mathrm{~km} \text { sejam } \\ 3.64 \mathrm{~km} \text { per hour } & 3.98 \mathrm{~km} \text { per hour }\end{array} \)

13. 60 और 72 के महत्तम समापवर्तक और लघुत्तम समापवत्व गुणनफल बराबर होगा (a) दोनों संख्याओं के योग के (b) दोनों संख्याओं के अन्तर के (c) दोनों संख्याओं के गुणनफल के (d) दोनों संख्याओं के भागफल के