10^6 has the same magnitude order of "a million", while 10^-4 is one mignitude order bellow "a thousandth".
Therefore, the numbers that must be grouped in the 10^6 column are 2,930,000, 5,000,000 and 4,030,000, while the numbers that must be grouped in the 10^-4 column are 0.0006, 0.00059 and 0.00012
