1.399 x 10^5 is the same as moving the decimal point over to the right five times.
Your answer would be 139,900.
1.6575 times 10 to the -5th power in standard form is 0.000016575
1.86 times 10 to the 5th power = 186,000
0.00040
870,000
420,000
0.0000804
7.36 in the 5th power = 12.41 10 to the 5th power = 20 12.41 x 20 = 303.2
5.843x10 to the 5th power is 584,300.
105 * 107 = 1012 = 1 trillion
20,000
0.0000252
118,125,000 or 1.18125 × 108