Answer: 3.32 * 10^4
Explanation:
1) Set up the equation
4.00 * 10^4 - 6.8 * 10^3
2) Set the scientific notions the same
You can do this by multiplying 10 or dividing 10 on a notion
4.00 * 10^4 - 0.68 * 10 ^4
3) Factor the scientific notions out
10^4(4.00 - 0.68)
4) Subtract
10^4(3.32)
3.32 * 10^4