Answer:
1. 3.22 x 10^-2
2. 2.822 x 10^-1
3. 3.402 x 10^-12
Step-by-step explanation:
1. 0.00000000023 x 140000000
= 2.3 x 10^-10 x 1.4 x 10^8
= 3.22 x 10^-2
2. 830000 x 0.00000034
= 8.3 x 10^5 x 3.4 x 10^-7
= 0.2822
= 2.822 x 10^-1
3. 0.00000042 x 0.0000081
= 4.2 x 10^-7 x 8.1 x 10^-6
= 3.402 x 10^-12
