1.	Express 0.0000421 in scientific notation.
		A.	4.21 × 10-4	B.	4.21 × 10-9
		C.	4.21 × 10-6	D.	4.21 × 10-5
		Hint
	2.	Express 3.157 ×10-4 in standard form.
		A.	31,570	B.	0.0003157
		C.	0.003157	D.	0.00003157
		Hint
	3.	Express 0.0000000139 in scientific notation.
		A.	1.39 × 10-8	B.	1.39 × 108
		C.	1.39 × 10-9	D.	1.39 × 10-7
		Hint
	4.	Write 0.0000055 in scientific notation.
		A.	5.5 × 10-6	B.	55 × 10-7
		C.	55 × 107	D.	5.5 × 106
		Hint
	5.	The amount of corn produced by the major corn-producing countries is given in the table. Order the countries according to the amount of corn produced from greatest to least.
		A.	Brazil, Mexico, France, United States, China	B.	France, Mexico, Brazil, China, United States
		C.	United States, China, Brazil, Mexico, France	D.	Brazil, United States, Mexico, France, China
		Hint