The value we are given in the question is 1.24 * 10^7. This form of writing number is called scientific notation. The standard notation is the normal, regular way of writing numbers. Scientific notation and standard notations are interchangeable.
1.24 * 10^7 written in standard notation will be = 1.24 * 10000000 = 12400000.
Thus, the mass of the meteoroid was 12400000 kg.
