How do I make the following numbers into three significant figures and express each in scientific notation?

Question

a) 143,700

b) 0.09750

c) 890,000

d) 6.764 times 10^4

e) 33,987.22

f) -6.5559

Answer 1

1.44 x 10^5

9.75 x 10^(-2)

8.90 x 10^5

6.76 x 10^4

3.40 x 10^4

-6.56 x 10^0

Answer 2

a)  1.44 x 10^5

b)  9.75 x 10^-2

c)  8.90 x 10^5

d)  6.76 x 10^4

e)  3.40 x 10^4

f)  -6.56 x 10^0