Question

What is each number written in scientific notation?
2. 1,220,000,000
a. 1.22 x 10
b. 0.122 x 10^10
c. 12.2 x 100^8
d. 1.22 x 10^9
3. 0.0287
a. 0.287 x 10^-1
b. 2.87 x 10^-2
c. 2.87 x 10
d. 28.7 x 100^-3

Answer 1

In scientific notation, you must have a single digit from 1 to 9 followed by some decimal
then multiplying by a power of base 10

for #2, that would rule out b) and c) immediately
clearly 1.22 x 10 = 12.2 , so a) is out also, ....

#3
0.0287 is a small number less than 1, so we expect of power of 10 to have a negative exponent,
ruling out c)
Using the other rule I stated above, what do you think?