Which of the following is greater than 4.3×10^9

A. 2.1 x 10^9
B. 3.2 x 10^9
C. 5.3 x 10^9
D. 7.4 x 10^8

2 answers

1 x 10^8 is 1 with 8 zeros that follow.
1 x 10^9 is 1 with 9 zeros that follow.
You should recognize that the last one is the smallest number there so the answer must be A,, B, or C.
With all of the numbers being something x 10^9. pick out the largest of the 10^9 numbers.
(Or explain why you have trouble identifying which is the smallest and which is largest.
How about I list this way:

A. 2.1 x 10^9
B. 3.2 x 10^9
C. 5.3 x 10^9
D. 0.74 x 10^9