Q. 7

Mass of one grain of rice is 0.00002 kg

$\Rightarrow 2 \times 10^{-5}$
1. $7.6 \times 10^6, 2.1 \times 10^7, 8.0 \times 10^7, 1.2 \times 10^8$
2. $\Delta Brazil \, and \, Vietnam \Rightarrow 2.1 \times 10^7 - 7.6 \times 10^6 \Rightarrow 21 \times 10^6 - 7.6 \times 10^6 \Rightarrow 13.4 \times 10^6 \Rightarrow 1.34 \times 10^7$