Answer:
see below
Step-by-step explanation:
4.2 x 10^6 − 1.2 x 10^5 − 2.5 x 10^5
All exponent have to have the same number
42 x 10^5 − 1.2 x 10^5 − 2.5 x 10^5
Subtract the number
42 - 1.2 - 2.5 = 38.3
Add back the exponent
38.3 * 10 ^5
This is not in scientific notation
Move the decimal one place to the left and add one to the exponent
3.83 * 10^6
3.3 x 10^9 + 2.6 x 10^9 + 7.7 x 10^8
All exponent have to have the same number
3.3 x 10^9 + 2.6 x 10^9 + .77 x 10^9
Add the numbers
3.3+2.6+.77 =6.67
Add back the exponent
6.67*10^9
This is in scientific notation
8.0 x 10^4 − 3.4 x 10^4 − 1.2 x 10^3
All exponent have to have the same number
8.0 x 10^4 − 3.4 x 10^4 − .12 x 10^4
Subtract
8.0 - 3.4 - .12 = 4.48
Add back the exponent
4.48* 10^4
This is in scientific notation
