β Math Β· Numbers and Algebra Β· Lesson 4 of 8 Β· 5 min
Comparing and ordering fractions, decimals and negatives
π Is 0.6 bigger than 0.58? Is β1/2 bigger than β3/4? These quick comparisons trip up more test takers than hard algebra does.
π‘ Key idea
Convert everything to decimals, line up the places, and remember that for negatives, closer to zero is greater.
π§ The idea
To compare numbers written in different forms, CONVERT them all to decimals, then compare digit by digit from the left. Padding with zeros helps: 0.6 = 0.60, which is greater than 0.58. A longer decimal is not automatically bigger; 0.125 is less than 0.2. To compare two fractions, you can also use a COMMON DENOMINATOR or CROSS-MULTIPLY: for 5/8 and 3/5, compare 5 Γ 5 = 25 with 8 Γ 3 = 24, so 5/8 is larger. On the NUMBER LINE, numbers grow to the right. That means negatives flip your intuition: β0.5 is greater than β0.75 because it sits closer to zero, and any negative is less than any positive. ASCENDING order runs least to greatest; DESCENDING runs greatest to least. Read the question twice to see which one it wants.
βοΈ Worked example
Order from least to greatest: 2/3, 0.6, 65%, 5/8.
Step 1: Convert: 2/3 β 0.667, 0.6 = 0.600, 65% = 0.650, 5/8 = 0.625.
Step 2: Compare the decimals: 0.600 < 0.625 < 0.650 < 0.667.
Step 3: Translate back to the original forms.
Answer: 0.6, 5/8, 65%, 2/3.
π Takeaways
- Turn every number into a decimal, then add zeros so they have the same length.
- Cross-multiply to compare two fractions quickly.
- On the number line, farther right is greater, even for negatives.
β Check yourself
Question 1 of 3
Which number is greatest?
- 0.09
- 0.1
- 0.089
- 0.0999
Show the answer and rationale
Answer: B
Pad to four places: 0.0900, 0.1000, 0.0890, 0.0999. The value 0.1 has a 1 in the tenths place, and the others have 0 there, so it is the greatest. The value 0.0999 looks bigger because it has more digits, but length does not decide size.
Question 2 of 3
Which list is in order from least to greatest?
- 1, 0, β2, β5
- 0, β2, β5, 1
- β5, β2, 0, 1
- β2, β5, 0, 1
Show the answer and rationale
Answer: C
On the number line β5 is farthest left, then β2, then 0, then 1. The list starting β2, β5 treats β5 as bigger because 5 is bigger than 2, and the list starting with 1 is in descending order.
Question 3 of 3
Which statement is true?
- 5/6 < 0.8
- 5/8 > 0.6
- 3/7 > 1/2
- 4/9 > 0.45
Show the answer and rationale
Answer: B
5/8 = 0.625, which is greater than 0.600. The others are false: 3/7 β 0.429 is less than 1/2, 4/9 β 0.444 is just under 0.450, and 5/6 β 0.833 is greater than 0.8, not less.
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