Step-by-step explanation:
[tex]a) \\ (8 \times {10}^{ - 3} ) \times (2 \times {10}^{ - 4} ) \\ = 8 \times 2 \times {10}^{ - 3} \times {10}^{ - 4} \\ = 16 \times {10}^{ - 3 - 4} \\ = 16 \times {10}^{ - 7} \\ = 1.6 \times {10}^{ - 6} \\ \\ b) \\ (6 \times {10}^{ 2} ) \div (3\times {10}^{ - 5} ) \\ \\ = \frac{6 \times {10}^{ 2}}{3\times {10}^{ - 5}} \\ \\ = \frac{2\times {10}^{ 2}}{ {10}^{ - 5}} \\ \\ = 2 \times {10}^{ 2 + 5} \\ \\ = 2 \times {10}^{7} \\ [/tex]
