Yes because when dealing with 10 squared times 10 to the fourth power you must multiply the exponents and you will get 10 to the sixth power.
No, 0.00036 is equivalent to 3.6 times ten to the negative fourth power.
17,200
81,990
4.61 x 106
10,000
10,000
7.4 x 10-4 = 0.00074
0.0001
10000
10,000
Five times ten to the third power is 5000 and three times ten to the second power is 300; 5000 + 300 = 5300.