4) A

Substitute the values given in the problem

4.6 x 10⁷ + 7 (2 x 10⁶)
4.6 x 10⁷ – 2 (2 x 10⁶)

(4.6 x 10⁷) + (14 x 10⁶)
(4.6 x 10⁷) – (4 x 10⁶)

(4.6 x 10⁷) + (1.4 x 10⁷)
(4.6 x 10⁷) – (0.4 x 10⁷)

  6 x 10⁷
4.2 x 10⁷

The two (10⁷) will cancel out

 6    =     1    =   10
4.2        0.7        7